Loading...

Table of Content

    28 September 2022, Volume 26 Issue 27 Previous Issue   
    For Selected: Toggle Thumbnails
    Effect of modified three-dimensional-printed titanium scaffold on osteogenic differentiation of adipose-derived mesenchymal stem cells
    Wang Jing, Yang Jiuju, Wang Ningning, Liu Chao
    2022, 26 (27):  4265-4271.  doi: 10.12307/2022.854
    Abstract ( 508 )   PDF (6447KB) ( 285 )   Save
    BACKGROUND: The three-dimensional (3D)-printed titanium scaffold overcomes the disadvantages of traditional titanium scaffolds, such as poor controllability of the internal structure and mismatch in shape. However, due to the relatively large biological inertia of titanium, it is difficult to combine with surrounding tissues quickly and stably after implantation in the body. 
    OBJECTIVE: To modify the surface of 3D-printed titanium by sandblasting acid etching and anodic oxidation and observe its effect on the adhesion, proliferation, and osteogenic differentiation of adipose-derived mesenchymal stem cells.
    METHODS: Micro-nano porous structure was constructed on the surface of 3D-printed titanium by sandblasting acid etching and anodic oxidation. The surface was characterized by scanning electron microscopy. Adipose-derived mesenchymal stem cells at passage 3 were inoculated in the Ti group (group A), Ti+osteogenic induction group (group B), and modified Ti group (group C). Cytoskeleton and CCK-8 assay were used to detect cell adhision and proliferation. Alkaline phosphatase staining and Alizarin red staining were used to observe osteogenesis. Real-time PCR was applied to analyze the expression of osteogenic genes. Immunofluorescence staining was employed to observe the expression of osteocalcin and osteopontin in cells. 
    RESULTS AND CONCLUSION: (1) Scanning electron microscopy showed that micro and submicron scale pits and grooves could be seen on the surface of the modified 3D-printed titanium scaffold. There were nanoscale pores with a diameter of 70-100 nm inside the scaffold and the pores were connected with each other. (2) Under a confocal microscope, there were few pseudopods and antennae in groups A and B, and they had not been spread; the cells in group C were completely spread on the surface of the material, and a large number of obvious pseudopods and antennae were visible, which were closely attached to the surface of the material. CCK-8 assay showed that modified 3D-printed titanium scaffolds could promote the proliferation of adipose-derived mesenchymal stem cells. (3) Alkaline phosphatase staining and Alizarin red staining exhibited that alkaline phosphatase activity and the mineralization ability were higher in the groups B and C than those in the group A (P < 0.05). (4) Osteocalcin, RUNX2, alkaline phosphatase, and type I collagen mRNA expression levels were higher in the groups B and C than those in the group A (P < 0.05). Osteopontin and osteocalcin protein expression levels were higher in the groups B and C than those in the group A (P < 0.05). (5) These results suggest that 3D-printed titanium scaffold modified by sandblasting acid etching and anodic oxidation has good biocompatibility and can promote the adhesion, proliferation and osteogenic differentiation of adipose-derived mesenchymal stem cells. 
    Figures and Tables | References | Related Articles | Metrics
    Bone cement injection for incomplete posterior wall osteoporotic fractures without neurological symptoms: a 4-year follow-up
    Wang Lingjun, Gu Yong, Feng Yu, Chen Liang, Lin Ziyu
    2022, 26 (27):  4279-4282.  doi: 10.12307/2022.856
    Abstract ( 593 )   PDF (802KB) ( 579 )   Save
    BACKGROUND: At present, there is considerable controversy in the treatment of osteoporotic patients with posterior wall rupture. Some scholars believe that it is a contraindication to bone cement augmentation and is suitable for open reduction and internal fixation; however, some scholars believed that osteoporosis can easily lead to failure of internal fixation, and minimally invasive bone cement augmentation can be performed under appropriate conditions.
    OBJECTIVE: To investigate the clinical effect of bone cement injection for incomplete posterior wall osteoporotic fractures without neurological symptoms. 
    METHODS: Data of 31 patients (12 males and 19 females; age range: 57 to 82 years old) with osteoporotic vertebral compression fracture with imcomplete posterior wall, which admitted to the First Affiliated Hospital of Soochow University from January 2011 to June 2013, were retrospectively analyzed. All patients were treated with balloon kyphoplasty, and the leakage of bone cement was evaluated. X-ray examination was carried out preoperatively, at 1 day, 3 months postoperatively and the last follow-up to measure the height of vertebral body and Cobb angle. The curative effect was evaluated by visual analogue scale score and Oswestry dysfunction index.
    RESULTS AND CONCLUSION: (1) Three out of 31 patients affected sidewall bone cement leakage and the patients had no remarkable neurological symptoms. (2) All 31 patients were followed up for a mean time of (47.2±24.3) months. At 1 day and 3 months and the last follow-up after treatment, the mean height of the vertebral body was higher than that before treatment (P < 0.05) and Cobb angle was smaller than that before treatment (P < 0.05). Visual analogue scale score and Oswestry dysfunction index were lower at 1 day and 3 months and the last follow-up after treatment than those before treatment (P < 0.05). (3) It is concluded that kyphoplasty is safe and effective in the treatment of osteoporotic vertebral compression fracture with incomplete posterior wall. It can dramatically relieve pain, increase the height of the vertebral body, and reduce kyphosis. 
    Figures and Tables | References | Related Articles | Metrics
    Nano hydroxyapatite/chitosan scaffold loaded with Akebia saponin D in bone defect repair
    Yun Xiao, Ding Tong, Yang Weiqiang, Guo Xinjun
    2022, 26 (27):  4293-4299.  doi: 10.12307/2022.858
    Abstract ( 560 )   PDF (1853KB) ( 969 )   Save
    BACKGROUND: Akebia saponin D can promote the proliferation and differentiation of osteoblasts, increase the activity and quantity of osteoblasts, and promote matrix calcification and callus growth. Akebia saponin D is mainly used to treat osteoporosis and promote fracture healing, and its application in bone defect repair is rare. 
    OBJECTIVE: To observe bone defects repaired by loading the sustained-release microspheres containing Akebia saponin D onto the nano hydroxyapatite/chitosan scaffold. 
    METHODS: The sustained-release microspheres containing Akebia saponin D were prepared by W/O/W method. The nano hydroxyapatite/chitosan scaffold of sustained-release microspheres containing Akebia saponin D (hereinafter referred to as the sustained-release scaffold) and the simple nano hydroxyapatite/chitosan scaffold (hereinafter referred to as blank scaffold) were prepared by freeze drying method to evaluate the in vitro drug release ability of sustained-release microspheres and the scaffold. Mouse-derived preosteoblast MC3T3-E1 was seeded on two kinds of scaffolds to analyze cell adhesion, proliferation, and differentiation. Individually cultured cells were used as controls. A 1.5-cm bone defect was made in the middle of bilateral radius of 24 adult New Zealand white rabbits. Blank scaffold and sustained-release scaffold were implanted, separately. Gross observation, Micro-CT imaging examination, and histological observation were performed at 4 and 12 weeks after operation.
    RESULTS AND CONCLUSION: (1) Both the sustained-release microspheres and sustained-release scaffolds containing Akebia saponin D had sustained-release effects. The drug release rate of sustained-release scaffold was more stable and lasting. (2) CCK-8 assay demonstrated that the cell proliferation rate on the sustained-release scaffold was significantly faster than that on the blank scaffold and control groups (P < 0.05). Under the scanning electron microscope, mouse-derived preosteoblast MC3T3-E1 was covered on the scaffolds of the two groups, and the number of cells on the sustained-release scaffolds was more than that on the blank scaffolds. (3) At 7 and 14 days of culture, alkaline phosphatase activity and Runx2 mRNA expression were higher in the sustained-release scaffold group than those in the blank scaffold group (P < 0.05). At 21 days of culture, osteopontin and osteocalcin expression levels in the sustained-release scaffold group were higher than those in the blank scaffold group (P < 0.05). (4) The results of imaging and histological observation showed that at 4 weeks after operation, a large number of new bone were found around the materials in the sustained-release scaffold group, and the new bone mass was significantly higher than that of the blank scaffold group. At 12 weeks after operation, a large number of new bones grew in the sustained-release scaffold, while only a small amount of new bones was found in the blank scaffold, and the material residue in the sustained-release scaffold group was significantly lower than that of the blank scaffold group (P < 0.05). (5) These results verify that nano hydroxyapatite/chitosan scaffold of sustained-release microspheres containing Akebia saponin D can enhance the adhesion, proliferation, and differentiation of osteoblasts in vitro, and promote the osteoinductive ability of nano hydroxyapatite/chitosan scaffold in vivo.
    Figures and Tables | References | Related Articles | Metrics
    Aligned poly(butylene adipate-co-terephthalate)/type I collagen fibers promote tendon-bone healing after anterior cruciate ligament rupture
    Hu Qiuyu, Yang Long, Yang Yong, Song Shenchao
    2022, 26 (27):  4314-4319.  doi: 10.12307/2022.861
    Abstract ( 629 )   PDF (1959KB) ( 257 )   Save
    BACKGROUND: The micro/nano structure on the surface of the material has a regulatory effect on the behavior of the cells. The tendon tissue is mainly composed of parallel collagen fibers, so the aligned fiber structure has a certain promotion effect on tendon-bone healing.
    OBJECTIVE: To explore the biocompatibility and osteoinductive activity of poly(butylene adipate-co-terephthalate) (PBAT)/type I collagen aligned fiber scaffolds.
    METHODS: Electrospinning technology was used to prepare random PBAT, aligned PBAT, and aligned PBAT/type I collagen fiber scaffold materials. The static contact angle and mechanical properties of the three stents were characterized. The three scaffolds were co-cultured with rat bone marrow mesenchymal stem cells to detect cell adhesion rate and proliferation. DAPI staining and Live/Dead fluorescent staining were used to observe cell adhesion and survival on the scaffold. Alkaline phosphatase staining and type I collagen immunohistochemical staining were used to detect the osteoinductive activity of oriented fiber scaffolds.
    RESULTS AND CONCLUSION: (1) The static contact angle of oriented PBAT/type I collagen fiber scaffold was lower than that of random PBAT and aligned PBAT fiber scaffolds (P < 0.05). (2) The strain degree of the two aligned scaffolds was better than that of the aligned PBAT scaffold (P < 0.05), and the tensile strength of the aligned PBAT scaffold was better than that of the random PBAT group (P < 0.05). There was no significant difference in the elastic modulus of the three groups of scaffolds (P > 0.05). (3) The cell adhesion and proliferation on the aligned PBAT/type I collagen fiber scaffold were better than those of the other two scaffolds. (4) DAPI staining and Live/Dead fluorescent staining showed that bone marrow mesenchymal stem cells could adhere and proliferate on the three groups of scaffolds, and the number of cells on the aligned PBAT/type I collagen fiber scaffold was the largest. (5) Alkaline phosphatase staining and type I collagen immunohistochemical staining showed that the osteoinductive activity of the aligned PBAT/type I collagen fiber scaffold was stronger than that of the aligned PBAT fiber scaffold. (6) The results show that the PBAT/type I collagen aligned fiber scaffold has good biocompatibility and osteoinductive activity and can effectively promote cell proliferation and adhesion.
    Figures and Tables | References | Related Articles | Metrics
    Effect of nanonized freshwater pearl powder on the expression of osteogenic related genes
    Liao Jun, Xu Pu
    2022, 26 (27):  4325-4329.  doi: 10.12307/2022.863
    Abstract ( 548 )   PDF (3857KB) ( 177 )   Save
    BACKGROUND: The high content of calcium ions in pearls can promote calcium salt deposition, inhibit the bone resorption activity of osteoclasts, and promote bone regeneration. The water-soluble protein contained in pearls has an osteoinductive effect and can promote the differentiation of osteoblasts. 
    OBJECTIVE: To observe the effect of nanonized freshwater pearl powder on the expression of osteogenic related genes in osteoblasts.
    METHODS: The mouse osteoblast MC3T3-E1 cells at passage 3 were taken and co-cultured with nano freshwater pearl powder (experimental group) and nano-hydroxyapatite (control group). The cells cultured separately were used as negative controls. At 7 days after culture, RT-PCR test was adopted to test the mRNA expression of Runx-related transcription factor II (Runx 2), osteopontin, and collagen type I.
    RESULTS AND CONCLUSION: (1) The mRNA expression of Runx2 and osteopontin increased in the experimental group and control group compared with the negative control group (P < 0.05). The mRNA expression of Runx2 and osteopontin was higher in the experimental group than that in the control group (P < 0.05). (2) The mRNA expression of collagen type I was higher in the experimental group than that in the control group and negative control group (P < 0.05). The difference in mRNA expression of collagen type I was not significantly different between the control group and negative control group (P > 0.05). (3) These results suggest that nanonized freshwater pearl powder can significantly promote the expression of Runx2, osteopontin, and collagen type I mRNA better than nano-hydroxyapatite.
    Figures and Tables | References | Related Articles | Metrics
    Comparison of the effects between two routes of total flavones of Rhizoma Drynariae administration on large segmental bone defects in rats based on bone tissue engineering technique
    Shen Zhen, Guo Ying, Jiang Ziwei, Zhang Yan, Li Zige, Chen Zehua, Ye Xiangling, Chen Guoqian
    2022, 26 (27):  4346-4352.  doi: 10.12307/2022.866
    Abstract ( 600 )   PDF (2631KB) ( 499 )   Save
    BACKGROUND: Composite scaffold has been proven to be effective in treating large segmental bone defects. However, slow bone repair and poor osteogenesis remain to be the main problem. Total flavones of Rhizoma Drynariae can promote osteogenesis and accelerate bone healing, but the route of administration is still confined to intragastric administration and the research about local drug delivery into bone defects is still relatively insufficient.  
    OBJECTIVE: To observe the difference between the local and intragastric administration of total flavones of Rhizoma Drynariae for large segmental bone defects by constructing the scaffold composed of total flavones of Rhizoma Drynariae controlled release microsphere-β-tricalcium phosphate. 
    METHODS: Three-dimensional printing technology was utilized to construct porous β-tricalcium phosphate scaffold. The ultrasonic emulsification solvent dialysis method was used to prepare total flavones of Rhizoma Drynariae sustained-release microspheres. The total flavones of Rhizoma Drynariae sustained-release microsphere/β-tricalcium phosphate scaffold was prepared by freeze-drying method. A total of forty SD rats were randomly divided into four groups, and a 3 mm long bone defect model of the tibia was constructed using the circular external fixation. No material was implanted in the bone defect of the blank group, and a simple β-tricalcium phosphate scaffold was placed in the blank scaffold group. A β-tricalcium phosphate scaffold was implanted in the gavage group that was combined with intragastric administration of total flavones of Rhizoma Drynariae, whereas the scaffold composed of total flavones of Rhizoma Drynariae controlled release microsphere-β-tricalcium phosphate was implanted in the drug loaded group. At 8 weeks after operation, imaging test, histological staining, and immunohistochemical staining were conducted. 
    RESULTS AND CONCLUSION: (1) X-ray films and Micro-CT examination showed that there was almost no callus formation in the defect area of the blank group. The callus generated in the blank scaffold group was connected to the osteotomy end, and the osteotomy line was faintly visible. The osteotomy line in the gavage group basically disappeared, and more new bones could be seen connecting both ends of the osteotomy site. In the drug loaded group, a large amount of callus formation was seen; the osteotomy line disappeared completely; the cortex was reconstructed well; and the medullary cavity was recanned. (2) Hematoxylin-eosin, Masson and Safranin Fast Green staining showed that a small amount of blood vessels and a large amount of connective tissue were seen in the defect area of the blank group. More bone matrix formation was seen in the blank scaffold group, but the maturity was not high. In the gavage group, a large amount of bone matrix was formed and mature. In the drug loaded group, a large amount of bone-like tissue was generated in the gap of the osteotomy defect; the cartilage tissue was highly mature, and the medullary cavity was recanalized. (3) Immunohistochemical staining results showed that compared with the blank scaffold group and blank group, transforming growth factor-β and bone morphogenetic protein 2 expression levels were higher in the gavage group and the drug loaded group (P < 0.05). Furthermore, above expression levels were higher in the drug loaded group than those in the gavage group (P < 0.05). (4) The above results indicated that both local administration and intragastric administration of total flavones of Rhizoma Drynariae could promote the repair of bone defects, but a significant difference was observed between the two methods, of which the local administration of controlled release microspheres of total flavones of Rhizoma Drynariae showed better effects.  
    Figures and Tables | References | Related Articles | Metrics
    Embedded percutaneous kyphoplasty and percutaneous vertebroplasty for treating post-traumatic vertebral osteonecrosis: finite element analysis of bone cement displacement
    Li Shiwen, Xi Chunyang, Wang Xiaoyan, Chen Jianbai, You Changcheng, Qiao Wentao, Xu Gongping
    2022, 26 (27):  4360-4366.  doi: 10.12307/2022.868
    Abstract ( 402 )   PDF (4240KB) ( 270 )   Save
    BACKGROUND: Important pathological feature of post-traumatic vertebral osteonecrosis is fissures in the injured vertebra body, bloody fluid and granulation in the fissures. The tissue can form a pseudomembrane. The pseudomembrane formed by necrotic material and granulation tissue can affect the penetration and distribution of the bone cement during vertebroplasty, which can affect the holding power of the bone cement, and increase the risk of bone cement displacement. 
    OBJECTIVE: To compare the risk of bone cement displacement in the vertebral body after the treatment of post-traumatic vertebral osteonecrosis with embedded percutaneous kyphoplasty and percutaneous vertebroplasty.   
    METHODS: Dicom data of postoperative thoracic CT of a female patient with post-traumatic vertebral osteonecrosis who received embedded percutaneous kyphoplasty treatment were collected. Mimics, Geomagic and Solidwork were utilized to construct three-dimensional embedded percutaneous kyphoplasty treatment models of T9-T11, then build percutaneous vertebroplasty treatment models (anchor point 100%). Embedded percutaneous kyphoplasty models with different size anchors (20%, 40%, 60%, and 80%) were constructed. The finite element analysis software Ansys was used to apply pressures of 150 N in the axial direction and 10 Nm of torque to simulate six movements: flexion, extension, left and right bending, and left and right rotation. The changes in the displacement of the bone cement were observed in the T10 vertebral body of the force model.  
    RESULTS AND CONCLUSION: (1) In the six states, the displacement of the bone cement in the T10 vertebral body of the 100% embedded percutaneous kyphoplasty model and the 20% embedded percutaneous kyphoplasty model was smaller than that of the percutaneous vertebroplasty model (P < 0.01). In the states of flexion, extension, right bending and left and right rotation, as the anchor point of the embedded percutaneous kyphoplasty model decreased, the displacement of the bone cement after the force gradually increased (P < 0.001). (2) It is concluded that the risk of bone cement displacement in the vertebral body of embedded percutaneous kyphoplasty treatment is less than that of the percutaneous vertebroplasty treatment in post-traumatic vertebral osteonecrosis. 
    Figures and Tables | References | Related Articles | Metrics
    Adjuvant treatment of nonunion of tibial fractures with platelet-rich plasma evaluated by bone turnover markers
    Hu Pengyu, Yu Zhiping, Jia Guanghou, Cong Zhichao, Cong Haibo
    2022, 26 (27):  4367-4373.  doi: 10.12307/2022.869
    Abstract ( 468 )   PDF (3064KB) ( 178 )   Save
    BACKGROUND: Due to the super-healing effect, platelet-rich plasma is gradually used in the clinic. Nevertheless, high-quality clinical comparative studies are currently absent to identify its effect on fracture nonunion and its action mechanism.
    OBJECTIVE: To compare the effects between platelet-rich plasma combined with surgery and surgery alone in the treatment of nonunion after tibial shaft fractures, and to analyze the corresponding laboratory indicators of fracture repair. 
    METHODS: Thirty patients with nonunion of tibial shaft fractures treated in Weihai Central Hospital Affiliated to Qingdao University from January 2017 to January 2020 were enrolled in this study. According to the second operation method, these patients were divided into platelet-rich plasma combined surgery group (n=16; autologous platelet-rich plasma injection once every other week for three injections) and operation group (n=14). Blood samples were taken from patients of the two groups to detect the levels of osteocalcin, bone alkaline phosphatase and β-I collagen carboxyl terminal peptide on the day of surgery (before surgery) and at 2, 4, 8, and 12 weeks after surgery. The surgical incision healing of the patients was observed between the two groups. At 3, 6, and 9 months after surgery, the callus and fracture line imaging scores and visual analogue scale scores were analyzed in the two groups, and the clinical healing and bone healing time were recorded in the two groups. The protocol was approved by the Ethics Committee of Weihai Central Hospital Affiliated to Qingdao University (approval No. 2016-Lunshen-07). 
    RESULTS AND CONCLUSION: (1) The levels of serum osteocalcin, bone alkaline phosphatase and β-I collagen carboxyl terminal peptide increased in the two groups after surgery. The osteocalcin level in the platelet-rich plasma combined surgery group was higher than that in the operation group at 2 and 4 weeks after surgery (P < 0.05). Bone alkaline phosphatase was higher in the platelet-rich plasma combined surgery group than that in the operation group at 2, 4, and 8 weeks after surgery (P < 0.05). The β-I collagen carboxyl terminal peptide level was higher in the platelet-rich plasma combined surgery group than that in the operation group after surgery (P < 0.05). (2) The grade A healing rates of incisions were 88% and 64% in the platelet-rich plasma combined surgery group and the operation group, respectively. The clinical fracture healing time and bone healing time were shorter in the platelet-rich plasma combined surgery group than those in the operation group (P < 0.05). (3) The imaging scores of callus and fracture line were higher in the platelet-rich plasma combined surgery group than those of the operation group at 3, 6, and 9 months after surgery (P < 0.05). Visual analogue scale scores were lower in the platelet-rich plasma combined surgery group than those of the operation group (P < 0.05). (4) These findings indicate that the effect of platelet-rich plasma combined with surgery for nonunion of tibial shaft fractures is better than that of surgery alone. Their combination can increase the serum levels of osteocalcin, bone alkaline phosphatase, and β-I collagen carboxyl terminal peptide, and is helpful to investigate the mechanism of platelet-rich plasma for fracture nonunion and to judge the clinical prognosis. 
    Figures and Tables | References | Related Articles | Metrics
    Preparation of copper loaded coating on polydopamine-modified polycaprolactone electrospun membrane and antibacterial and cellular properties evaluation
    Dong Xiling, Hui Min, Cao Fei, Lin Peng, Zhou Han, Wang Le, Zhang Xiaoming, Liu Tongbin
    2022, 26 (27):  4272-4278.  doi: 10.12307/2022.855
    Abstract ( 769 )   PDF (2411KB) ( 367 )   Save
    BACKGROUND: In the field of oral cavity, the guided bone tissue regeneration membrane is widely used in oral implant, periodontal and maxillofacial surgery to achieve rapid and effective tissue regeneration. However, how to prevent the infection around the implant has always been a problem to be solved.
    OBJECTIVE: To prepare polycaprolactone electrospun fiber, and to modify its surface with polydopamine and adhere to copper ions, so as to prepare a guided bone tissue regeneration membrane with dual functions of antibacterium and osteogenesis. 
    METHODS: Polycaprolactone electrospun membrane, polydopamine modified polycaprolactone electrospun membrane and copper (0.01, 0.1, 1 mol/L) loaded polydopamine modified polycaprolactone electrospun membrane were prepared, separately. MC3T3-E1 cells were seeded on the electrospun membrane and cell proliferation was detected by CCK-8 assay. Streptococcus mutans was co-cultured with the electrospun membrane to detect the antibacterial rate. According to the results of CCK-8 assay and inhibition rate experiment, the suitable copper loading concentration was determined for subsequent experiments. The in vitro sustained release properties of copper loaded polydopamine modified polycaprolactone electrospun membrane were detected. MC3T3-E1 cells were seeded on the three kinds of electrospun membranes, separately. The cell viability was analyzed by live/dead cell staining and the early osteogenic differentiation was evaluated by alkaline phosphatase staining. Streptococcus mutans was co-cultured with three kinds of electrospun membranes and the antibacterial activity of electrospun membranes was evaluated by live/dead bacterial staining.
    RESULTS AND CONCLUSION: (1) CCK-8 results showed that copper (0.01, 0.1 mol/L) loaded polydopamine modified polycaprolactone electrospun membrane could promote the proliferation of MC3T3-E1 cells. Copper (1 mol/L) loaded electrospun membrane inhibited the proliferation of MC3T3-E1 cells. The antibacterial rate of copper loaded electrospun membrane was higher than that of polycaprolactone electrospun membrane and polydopamine modified polycaprolactone electrospun membrane. The antibacterial rate of copper (0.1 mol/L) loaded electrospun membrane was higher than that of copper (0.01 mol/L) loaded electrospun membrane. Based on the above experimental results, 0.1 mol/L copper loaded electrospun membrane was selected for further study. (2) The concentration of copper ion released from the electrospun membrane on the 28th day in vitro was about 5.26 mg/L (82.8 μmol/L), which was in the range of non-cytotoxic and effective antibacterial concentration (10 -4-10-5 mol/L). (3) The results of live/dead staining showed that the copper loaded electrospun membrane had good biocompatibility and antibacterial activity. (4) Alkaline phosphatase staining showed that the osteogenic ability of polydopamine modified polycaprolactone electrospun membrane and copper loaded electrospun membrane was higher than that of Polycaprolactone electrospun membrane. (5) The results showed that copper loaded polydopamine modified polycaprolactone electrospun membrane had good bone promoting and antibacterial properties.
    Figures and Tables | References | Related Articles | Metrics
    Properties of injectable gluconolactone-sodium alginate/beta-tricalcium phosphate/polyethylene glycol composite hydrogel scaffold
    Liu Yin, Liu Qin, Chen Jiao, Gu Xianyang, Chen Jiawen, Ma Minxian
    2022, 26 (27):  4308-4313.  doi: 10.12307/2022.860
    Abstract ( 668 )   PDF (1639KB) ( 232 )   Save
    BACKGROUND: Injectable sodium alginate hydrogel can repair bone defects by non-invasive or minimally invasive methods, but the mechanical properties are poor and polyethylene glycol-based hydrogel has elasticity. The composite of materials is expected to improve the mechanical properties and cellular biocompatibility of hydrogel scaffolds.
    OBJECTIVE: To investigate the physical and chemical properties of glucolactone-sodium alginate/β-tricalcium phosphate-polyethylene glycol hydrogel and its effect on the proliferation and differentiation of murine bone marrow mesenchymal stem cells. 
    METHODS: Gluconolactone as cross-linking agent was set to prepare glucolactone-sodium alginate/β-tricalcium phosphate-polyethylene glycol hydrogel (concentrations of cross-linking agent were 5, 10, and 20 g/L, respectively, which were marked as groups A, B, and C) and glucolactone-sodium alginate/β-tricalcium phosphate hydrogel (concentration of cross-linking agent was 10 g/L, which was marked as group D). The morphology, mechanical properties, and gelation time of hydrogels in the four groups were characterized. Rat bone marrow mesenchymal stem cells were co-cultured with four groups of hydrogels. The proliferation of cells was detected by CCK-8 assay. Cell survival was observed by Live/Dead fluorescence staining. Osteogenic differentiation was detected by immunocytochemical staining of type I collagen. 
    RESULTS AND CONCLUSION: (1) The filamentous structure similar to adhesion was observed by scanning electron microscope in the groups A, B and C. The pore size distribution of group A was uneven. The pore size of group B was uniform and the porosity was high. The group C had high porosity but different pore sizes. The group D had uneven pore size distribution and low porosity. (2) Physicochemical properties: The compressive stress in group B was higher than that in group D (P < 0.05). With the increase of gluconolactone concentration, the compressive stress of hydrogel in groups A, B and C increased (P < 0.05). The macroscopic performance of hydrogel after 50% compression showed that there were larger cracks in group D and only smaller cracks in group B after compression. The gelation time of groups A, B and C shortened with the increase of gluconolactone concentration, and the gelation time of group B was slightly longer than that of group D (P < 0.05). (3) CCK-8 assay showed that the cell proliferation rate of groups A and B was higher than that of group C (P < 0.05), and that of group B was higher than that of group D (P < 0.05). Live/Dead staining showed that the cell survival rate of each group was higher, but the number of dead cells was more in group C than that in the other three groups. (4) Immunocytochemical staining showed that the cells in groups A, B, and D were polygonal, and the cells in group C were partially round. The green fluorescence intensity in group B was higher than that in the other three groups, and the morphology of the cytoskeleton and microfilaments and the number of cells were also better than those in the other three groups. (5) The results show that the glucolactone-sodium alginate/β-tricalcium phosphate-polyethylene glycol hydrogel has perfect mechanical properties and stability; hydrogel prepared with 10 g/L gluconolactone can effectively promote the proliferation and differentiation of murine bone marrow mesenchymal stem cells.
    Figures and Tables | References | Related Articles | Metrics
    Expression and significance of collagen fiber and matrix metalloproteinase-9 during orthodontic root resorption in rats
    Liu Ke, Fan Haixia, Wang Hong, Cheng Huanzhi, Geng Haixia
    2022, 26 (27):  4288-4292.  doi: 10.12307/2022.902
    Abstract ( 528 )   PDF (3014KB) ( 218 )   Save
    BACKGROUND: Root resorption is the most common complication in orthodontic treatment, and is also a hot topic in current orthodontic research. Currently, the remodeling process of collagen fibers in the inferior periodontal tissue and its relationship with matrix metalloproteinase-9 remain unclear at different time points during root resorption.
    OBJECTIVE: To investigate the remodeling of collagen fibers and the expression of matrix metalloproteinase-9 in the inferior periodontal tissue at different time points on the pressure side during orthodontic root resorption.
    METHODS: Thirty eight-week-old male Wistar rats were selected, and the orthodontic tooth movement model was established by pulling the left maxillary first molars towards the near middle in the experimental group, and the right side was not treated as the control group. The changes of collagen fibers and expression of matrix metalloproteinase-9 in alveolar bone, root surface and periodontal tissue at 1, 3, 5, 7, 14, and 21 days were observed and analyzed by histomorphology after force application. 
    RESULTS AND CONCLUSION: (1) Hematoxylin-eosin staining and Masson's trichrome staining results confirmed that compared with the control group, the alveolar bone and tooth root surface of the experimental group had different degrees of resorption. The periodontal tissue collagen fibers underwent structural remodeling. The remodeling was most significant at 7 and 21 days. The expression of collagen fibers per unit area decreased first and then increased with the extension of the force. (2) Immunohistochemical staining confirmed that compared with the control group, the expression of matrix metalloproteinase-9 in the experimental group increased. The expression level showed a trend of first increasing and then decreasing with the extension of the application time. Pearson correlation analysis confirmed that the matrix metalloproteinase-9 expression was negatively correlated with the expression of collagen fibers in periodontal tissues (r=-0.933, P < 0.01). (3) The above results indicate that during orthodontic tooth root resorption in rats, the collagen in periodontal tissues is prolonged with time of stress. The expression level of matrix metalloproteinase-9 is related to the dynamic changes of collagen fibers and the changing trend of tooth root resorption.
    Figures and Tables | References | Related Articles | Metrics
    Effect of grain boundary segregation on low-temperature aging of 3% yttrium oxide stabilized zirconia ceramics co-doped with GeO2 and TiO2
    Zhou Zhiwei, Niu Wanqiong, Ren Lijuan, Wang Zhenhua
    2022, 26 (27):  4320-4324.  doi: 10.12307/2022.862
    Abstract ( 559 )   PDF (6301KB) ( 520 )   Save
    BACKGROUND: Many recent studies have found that zirconia co-doped with TiO2 and GeO2 exhibits excellent superplasticity. 
    OBJECTIVE: To investigate the improvement of anti-cryogenic aging properties of zirconia materials stabilized by 3% yttrium oxide co-doped with TiO2 and GeO2.
    METHODS: The 3% yttrium oxide stabilized zirconia material samples co-doped with GeO2 and TiO2 were prepared by mechanical ball milling, drying, and pressure free sintering. Among them, the mole percentage of 3% yttrium oxide stabilized zirconia was 98%. The mole percentages of TiO2 powder (purity 99.8%) and GeO2 powder were 1.5% and 0.5%, respectively, which was recorded as the 1.5Ti-0.5Ge group. The mole percentages TiO2 powder (purity) 99.99%) and GeO2 powder were 1% and 1%, respectively, which was recorded as 1Ti-1Ge group. The mole percentages of TiO2 powder (purity 99.8%) and GeO2 powder were 0.5%, 1.5%, respectively, which was recorded as 0.5Ti- 1.5Ge group. The microstructure of all samples was investigated by scanning transmission electron microscopy and energy spectroscopy. After treatment in an autoclave, the conversion of all samples was measured by an X-ray diffractometer.
    RESULTS AND CONCLUSION: (1) Scanning transmission electron microscopy results showed that the composite powders of a 3% yttrium oxide stabilized zirconia material co-doped with GeO2 and TiO2 had uniform particle size and were distributed over a 50 nm; the particle shape was basically spherical and well dispersed, but there was a small amount of agglomeration. X-ray diffractometer exhibited that the Ge4+, Ti4+ stabilizers could inhibit the low-temperature aging effect of zirconia materials. With the increase of the doping amount of GeO2, the low-temperature aging resistance of zirconia could be improved. Energy spectrometer detection demonstrated that with the increase of dopant content, the degree of grain boundary segregation increased, but even if the doping amount of Ge4+ was small, the degree of grain boundary segregation could be comparable to that of Ti4+ with a large amount of doping. (2) The results suggest that the addition of GeO2 and TiO2 improved 3% yttrium oxide stabilized zirconia ceramics against low-temperature aging properties. GeO2 is superior to TiO2 in resisting low-temperature aging and can be used as the first choice. 
    Figures and Tables | References | Related Articles | Metrics
    Effect of Physiological Anchorage Spee’s Wire System combined with micro-implant anchorage on jaw plane angle and chin shape in patients with maxillary protrusion in the vertical direction
    Tian Bingxin, Sun Liting, Feng Zhe, Ma Tao
    2022, 26 (27):  4330-4334.  doi: 10.12307/2022.864
    Abstract ( 598 )   PDF (1482KB) ( 196 )   Save
    BACKGROUND: At present, the research on the performance of Physiological Anchorage Spee's Wire System (PASS) appliance in China is still in its infancy. Quantitative analysis of the effect of vertical anchorage control using PASS appliance for teenagers is seldom reported.
    OBJECTIVE: To analyze the relationship between the vertical anchorage control and the changes of jaw plane angle and chin shape in patients with maxillary protrusion treated by PASS appliance. 
    METHODS: 120 patients with maxillary protrusion were treated in the Second Affiliated Hospital of Xingtai Medical College from March 2016 to March 2019. The patients undergoing micro-implant anchorage treatment were randomly divided into observation group and control group, with 60 patients in each group. PASS appliance was used in the control group, and vertical support appliance between the first molars of both sides was used in the observation group. Oral X-ray lateral radiographs were used for imaging diagnosis to compare the effect and the difference of the chin shape between the two groups. 
    RESULTS AND CONCLUSION: (1) At 4 weeks after treatment, the inner lower angle between the upper central incisor and the anterior skull base plane, the inner upper angle between the long axis of the lower central incisor and the mandibular plane, the angle of the mandibular plane, the distance between the two feet, and the distance from the lower lip bump to the aesthetic plane were significantly lower in the observation group than those of the control group (P < 0.05). The angle of the long axis of the upper and lower central incisors was significantly higher in the observation group than that of the control group (P < 0.05). (2) At 4 weeks after treatment, the apical point chin thickness, anterior chin thickness, chin depression, chin inclination, and chin soft tissue thickness of the observation group were significantly lower than those of the control group (P < 0.05), and the chin height, chin protrusion, and chin curvature and the depth of the soft tissue depression of the chin were significantly higher than those of the control group (P < 0.05). (3) It is concluded that in the treatment of patients with malocclusion, compared with PASS appliance, micro-implant anchorage combined with vertical control measures can effectively improve the shape of the chin, and the effect is significant.
    Figures and Tables | References | Related Articles | Metrics
    Clinical applicability of cobalt-chromium metal-ceramic crowns with porcelain margin
    Chen Xi, Cheng Hui, Chen Jiahui, Li Xiurong
    2022, 26 (27):  4374-4378.  doi: 10.12307/2022.870
    Abstract ( 656 )   PDF (860KB) ( 188 )   Save
    BACKGROUND: Some researchers have pointed out that the porcelain edge design can well solve the problem of “gingival black line” of metal ceramic crown in anterior tooth restoration, but the mechanical research methods used to test its strength cannot simulate the real strength of metal ceramic crown under the influence of humid environment and fatigue in oral environment.  
    OBJECTIVE: To discuss clinical suitability of porcelain crowns with porcelain edge design by comparing the fatigue life and strength of cobalt-chromium metal crowns with porcelain edge design in simulated oral environment.  
    METHODS: Sixty cobalt-chromium metal crowns were prepared. The cobalt-chromium metal porcelain crowns with the metal abutment edge ending at the middle of the shoulder (conventional design) were considered as group A (n=20); the metal abutment edge ending at the junction of the shoulder and the axial wall was considered as group B (n=20); and the metal abutment edge ending 1 mm above the junction of the shoulder and the axial wall was considered as group C (n=20). All samples were immersed in artificial saliva and placed at a constant temperature of 37 ℃ for 24 hours. Subsequently, the samples were subjected to fatigue cycles on an electromagnetic fatigue tester with a loading force of 50 N. The samples were removed after 0.75 million and 1.5 million cycles respectively, to observe the surface condition. The samples without porcelain breaking were transferred to the universal material testing machine for static loading until porcelain breaking and the load force borne by each sample at the time of porcelain breaking was recorded.  
    RESULTS AND CONCLUSION: (1) After 0.75 million and 1.5 million cycles, porcelain breaking was not observed in all specimens and no cracks were observed on the surface of all porcelain crowns. (2) The average load force value of the specimens in group A was the largest, about 1 785 N; the average load force value of the specimens in group B was the second, about 1 426 N; the average load force value of the specimens in group C was the smallest, about 1 134 N. There was a significant difference in the load force value among the three groups (P < 0.05). (3) The fatigue life of the three kinds of ceramic crowns with edge design is more than ten years, and their strength can also meet the needs of normal occlusion.
    Figures and Tables | References | Related Articles | Metrics
    Platelet-rich fibrin combined with curcumin nanoparticle hydrogel promotes wound healing in diabetic mice
    Wu Haineng, Geng Kang, Wang Jing, Xiong Aibing
    2022, 26 (27):  4300-4307.  doi: 10.12307/2022.859
    Abstract ( 749 )   PDF (7691KB) ( 913 )   Save
    BACKGROUND:  At present, there is still a lack of ideal treatment methods for refractory diabetic wounds. It is of great significance to explore methods to promote diabetic wounds healing.
    OBJECTIVE: To observe the effect of platelet-rich fibrin combined with curcumin nanoparticles hydrogel on wound healing in diabetic mice. 
    METHODS: Platelet-rich fibrin combined with curcumin nanoparticles hydrogel was prepared. 100 healthy adult C57BL/6J mice were randomly divided into normal control group (A group, n=20) and diabetic group (n=80). After model establishment, round full-thickness skin injury wounds were made in 72 mice by skin punch with a diameter of 1 cm. Seventy-two diabetic mice were randomly divided into diabetic control group (B group; physiological saline; n=18), platelet-rich fibrin + free curcumin group (C group; n=18), platelet-rich fibrin + curcumin nanoparticles group (D group; n=18), and platelet-rich fibrin + curcumin nanoparticles hydrogel group (E group; n=18). Round full-thickness skin injury wounds were made with a diameter of 1 cm in mice of A group and treated with physiological saline. The drug administration was started on the day of wound modeling, and the above-mentioned corresponding drugs were administered every other day until post-injury 12 days. On days 3, 9, and 12 after treatment, wound healing and histopathological changes of wound margin were observed. 
    RESULTS AND CONCLUSION: (1) On day 12 after treatment, the wounds in A, C, D, and E groups were basically healed completely, but the wounds in B group were not completely healed. The wound healing rate of E group was higher than that of B, C, and D groups (P < 0.05). (2) On day 3 after treatment, hematoxylin-eosin staining showed that the wound healing in E group was better than that in B, C, and D groups, and the inflammatory cell infiltration and granulation maturity were the closest to the A group. (3) Immunohistochemical staining showed that the mean number of Ly6G+ cells in the wound on day 3 after treatment in E group was lower than that in B and C groups (P < 0.001), and the mean number of F4/80+ cells in E group was lower than that in B, C and D groups on day 9 after treatment (P < 0.001). The number of CD31+ cells in the wound on day 12 after treatment in group E was higher than that in B, C and D groups (P < 0.01). (4) Immunofluorescence staining on day 9 after treatment showed that the number of M2-type macrophages in the wounds of E group was higher than that of B, C, and D groups (P < 0.01), and the number of M1-type macrophages was lower than that of B, C, and D groups (P < 0.001). (5) Masson staining on day 12 after treatment showed that there were a large number of neatly arranged, evenly distributed and dense collagen fibers in A, C, D, and E groups, among which A and E groups demonstrated more collagen and deep staining; group B presented loose collagen fibers, uneven distribution, pale color, and small quantity. (6) Platelet-rich fibrin combined with curcumin nanoparticles hydrogel can improve the inflammatory environment of diabetic wound and promote wound healing in diabetic mice.
    Figures and Tables | References | Related Articles | Metrics
    Effect of curcumin nanoparticles on proliferation of human retinal pigment epithelial cells
    Zheng Haisheng, Lan Yuqing, Zhong Xingwu, Ding Hui
    2022, 26 (27):  4335-4339.  doi: 10.12307/2022.834
    Abstract ( 507 )   PDF (5594KB) ( 141 )   Save
    BACKGROUND: Curcumin can inhibit the proliferation of human retinal pigment epithelial cells and anti-angiogenesis and can play an important role in the prevention and treatment of fundus neovascularization. However, its water solubility is poor and its half-life in the body is short. It requires long-term and multiple injections. Therefore, the development of a new dosage form of curcumin has an important clinical significance. 
    OBJECTIVE: To study the synthesis of deoxycholic acid group grafted chitosan derivatives loaded curcumin nanoparticles and the effect of curcumin nanoparticles on the proliferation of human retinal pigment epithelial cells. 
    METHODS: Chitosan-deoxycholic acid nanoparticles were prepared, and then curcumin/chitosan-deoxycholic acid nanoparticles were prepared to detect the drug loading, loading efficiency and in vitro drug release performance of curcumin/chitosan-deoxycholic acid nanoparticles. Human retinal pigment epithelial cells were co-cultured with curcumin (5, 10, 20, 40 mg/L), chitosan-deoxycholic acid nanoparticles (5, 10, 20, 40 mg/L), and curcumin/chitosan-deoxycholic acid nanoparticles (5, 10, 20, 40 mg/L). Cell proliferation was detected by the CCK-8 assay. 
    RESULTS AND CONCLUSION: (1) The drug loading and loading efficiency of curcumin/chitosan-deoxycholic acid nanoparticles were 27.5% and 55%, respectively. Within the first 10 hours in vitro, the nanoparticles had a drug burst phenomenon, slowly released and then reached a balance until 96 hours later, and the cumulative amount of drug release was 31.6%. (2) The chitosan-deoxycholic acid nanoparticles of different mass concentrations had no significant effect on the proliferation of human retinal pigment epithelial cells after 24 and 48 hours of culture. (3) The curcumin of different mass concentrations and curcumin/chitosan-deoxycholic acid nanoparticles could suppress the proliferation of human retinal pigment epithelial cells in time- and mass-concentration-dependent manners. At the same mass concentration, the inhibition rate of cell proliferation of curcumin/chitosan-deoxycholic acid nanoparticles at 1-4 days of culture was lower than that of the curcumin group (P < 0.05). There was no significant difference in the inhibition rate of cell proliferation between the two groups cultured for 5 and 6 days (P > 0.05). (4) The results show that the curcumin-loaded chitosan-deoxycholic acid nanoparticles have an inhibitory effect on human retinal pigment epithelial cells, and the nanoparticles did not reduce the biological activity of the curcumin ingredients. 
    Figures and Tables | References | Related Articles | Metrics
    Biocompatibility of silk fibroin/type II collagen/hydroxyapatite three-phase composite scaffold
    Sun Kai, Li Ruixin, Gao Lilan, Fan Meng, Zhang Xizheng, Li Hui
    2022, 26 (27):  4283-4287.  doi: 10.12307/2022.857
    Abstract ( 573 )   PDF (6258KB) ( 192 )   Save
    BACKGROUND: To repair cartilage, cartilage calcification layer, and bone tissue at the same time, it is necessary to design a heterogeneous scaffold and add an intermediate layer that mimics the cartilage calcification layer of natural bone cartilage tissue. The three-layer structure of three-phase scaffold can reconstruct cartilage, calcified cartilage, and subchondral bone at the same time, so as to realize the integration of bone and cartilage repair.
    OBJECTIVE: To construct silk fibroin/type II collagen/hydroxyapatite three-phase composite, and to study its physicochemical properties and biocompatibility. 
    METHODS: Silk fibroin/type II collagen/hydroxyapatite three-phase composite was constructed by uneven sedimentation and low-temperature 3D printing. The porosity, water absorption expansion rate, and mechanical properties of the composite were detected. Mouse chondrocyte ADTC-5 was seeded on the surface of the scaffold. The distribution, adhesion, and extension of chondrocytes on the scaffold were observed under a scanning electron microscope. MTT assay was used to detect cell proliferation. Hematoxylin-eosin staining was used to observe the cell-scaffold composite morphology. 
    RESULTS AND CONCLUSION: (1) The composite scaffold was malleable and viscoelastic, with a porosity of (97.7±1.5)%, a water absorption expansion rate of (1 410.95±66.55)%, and an elastic modulus of (35.3±2.5) kPa. Under the scanning electron microscope, the pore network structure of the composite could be seen, with good connectivity of each pore, large pore diameter of (210.5±20.5) μm, small pore diameter of (75.5±16.5) μm, porosity (97.7±1.5)%, and average wall thickness (92.5±18.5) μm. (2) After 3 days of culture, chondrocytes adhered to the internal pores of the scaffold and secreted a large amount of extracellular matrix under the scanning electron microscope, and the cell morphology was distinct. (3) MTT assay exhibited that with the extension of the culture time, the chondrocytes on the scaffold continued to proliferate. (4) Hematoxylin-eosin staining demonstrated that after 3 days of co-culture, chondrocytes grew adherently along the internal voids of the scaffold material, with a fusiform shape, dispersed distribution and a small number. After 14 days of co-culture, the number of cells increased significantly. Cells grew like a colony, and the connections between cells could be clearly seen. (5) These findings verify that silk fibroin/type II collagen/hydroxyapatite composite prepared by uneven sedimentation technology has good physical and chemical properties and biocompatibility. 
    Figures and Tables | References | Related Articles | Metrics
    Hydrogel loaded anti-caries DNA vaccine pVAX1-SpaP/P produces immune effects in four ways
    Li Hu, Guan Xiaoyan, Li Min, Dong Jingnan, Xiao Qianwen, Bai Guohui, Wang Mingwei, Liu Jianguo
    2022, 26 (27):  4340-4345.  doi: 10.12307/2022.865
    Abstract ( 580 )   PDF (2298KB) ( 132 )   Save
    BACKGROUND: Due to low price, safety and effectiveness, anti caries DNA vaccine is expected to become an important means of human anti caries. Scholars are looking for an effective immune pathway to induce antibody production or a sustained-release system and adjuvant to protect vaccine titer, which has become a research focus in recent years. 
    OBJECTIVE: To observe the immune effect of the sustained release hydrogel poly(lactic/glycolic acid)-polyethylene glycol-poly(lactic/glycolic acid) loaded with anti-caries gene vaccine pVAX1-SpaP/P. 
    METHODS: The recombinant plasmid pVAX1-SpaP/P and the empty plasmid pVAX1 were loaded with poly(lactic/glycolic acid)-polyethylene glycol-poly(lactic/glycolic acid) hydrogel, respectively. Twenty-eight New Zealand white rabbits were randomly divided into seven groups. Quadriceps femoris injection, submandibular gland subcutaneous injection, oral administration, and nasal drip injection of hydrogel loaded with recombinant plasmid pVAX1-SpaP/P were performed in four groups. The remaining groups were the control groups. In the negative control group 1, quadriceps muscle was injected with hydrogel loaded with empty plasmid pVAX1. In the negative control group 2, hydrogel loaded with empty plasmid pVAX1 was orally taken. The quadriceps femoris of the blank control group was injected with saline. The immunization was enhanced once a week after the initial immunization. The second immunization was conducted one week apart, and immunized for the third time after an interval of two weeks. ELISA was used to detect anti-SpaP IgA antibody in saliva and anti-SpaP IgG antibody in serum before and after immunization. At 3 days after the end of the three immunizations, the expression of pVAX1-SpaP/P protein was observed by immunohistochemistry technique. 
    RESULTS AND CONCLUSION: (1) Two weeks after immunization with hydrogels loaded with recombinant plasmid pVAX1-SpaP/P via different pathways, the levels of anti-SpaP IgA antibody in saliva and anti-SpaP IgG antibody in serum were significantly increased in rabbits. Anti-SpaP IgG antibody level reached a peak at 10 weeks; anti-SpaP IgA antibody level reached a peak at 6 weeks. Anti-SpaP IgG antibody levels in the oral group were higher than those in the other six groups at 6-12 weeks (P < 0.05). Anti-SpaP IgA antibody levels were higher in the submandibular gland group than those in the other six groups at 4-8 weeks (P < 0.05). (2) One week after immunization with hydrogels loaded with recombinant plasmid pVAX1-SpaP/P via different pathways, anti-SpaP IgA antibody levels increased and peaked at 8 weeks. The antibody levels were higher in the submandibular gland group than those in the other six groups at 1-6 weeks (P < 0.05). The antibody levels were higher in the oral group than those in the other six groups at 8-12 weeks (P < 0.05). Anti-SpaP IgG antibody level in rabbit saliva began to increase at 2 weeks after immunization, and reached a peak at 10 weeks. The antibody levels of the oral group were higher than those in the other six groups at 2, 3, and 6 weeks (P < 0.05). The antibody levels of the quadriceps femoris group at 10 weeks were higher than those of the other six groups (P < 0.05). (3) After immunization with hydrogels loaded with recombinant plasmid pVAX1-SpaP/P via different pathways, immunohistochemical staining showed that positive pVAX1-SpaP/P protein expression in the injection site tissues. (4) The results showed that the poly(lactic/glycolic acid)-polyethylene glycol-poly(lactic/glycolic acid) hydrogel loaded pVAX1-SpaP/P anti caries vaccine could induce specific antibody production in the four ways to induce the immune effect and maintain long time.
    Figures and Tables | References | Related Articles | Metrics
    Hemostatic efficacy, degradation in vivo and biological evaluation of fish scale collagen
    Chen Yue, Luo Feng, Su Dan, Yang Diyuan, Pu Qi, Zhang Min, Gui Wenjuan, Sun Xiaorong
    2022, 26 (27):  4353-4359.  doi: 10.12307/2022.867
    Abstract ( 767 )   PDF (2774KB) ( 292 )   Save
    BACKGROUND: Absorbable hemostatic materials are currently a hot field of hemostatic materials. The clinical demand for safe and effective absorbable hemostatic materials is increasing. Fish scale collagen is not only safe and effective, but also can turn fish scales into treasures and make full use of resources reasonably.
    OBJECTIVE: To verify the hemostatic efficacy, the degradation procedure in vivo, and explore the safety of fish scale collagen.
    METHODS: Fish scale collagen material was extracted by chemical decalcification combined with low temperature enzymatic method, and used in the following three tests. (1) The First Part: The bleeding test included the body-liver bleeding and surface-tail bleeding. Liver bleeding and tail hemorrhage model was prepared by physical damage to the liver and tail. Model animals were divided into experimental group (use of fish scale collagen), the control group (use of hemostatic sponge), and blank group (no processing). The amount of blood loss and hemostatic time were recorded. (2) Part II: In vivo degradation test of fish scale collagen: Animals with liver hemostasis were euthanized at 1, 3, 5, 10, 20, 30, 40, 50, and 60 days after being filled with fish scale collagen material. Animals in the control group were euthanized at 5 and 50 days after being filled with hemostatic sponge. Animals in the blank group were euthanized at 5 and 50 days after modeling. The adhesions in abdominal cavity were observed, and the degradation of material and the progress of liver regeneration were observed pathologically. (3) Part III: Biological evaluation, including hemolysis test, epidermal stimulation test, intradermal stimulation test, pyrogen test, and acute toxicity test.
    RESULTS AND CONCLUSION: (1) The collagen of filamentous fish scale was extracted successfully by chemical decalcification combined with low temperature enzymatic method; the yield was 66%-73%, and the pore size of collagen of fish scale was 0.80±0.23 mm. (2) Tail bleeding model was used to verify the hemostatic effect of body surface. Compared with the blank group, the hemostatic time of fish scale collagen was significantly shortened, and the amount of blood loss was significantly reduced compared with the control group (hemostatic sponge) and the blank group (P < 0.05). (3) At 5 days after implantation, the collagen of fish scale was closely attached to the damaged liver without intraperitoneal adhesion. At 20 days after implantation, the volume of collagen of fish scale was significantly reduced; 50 days after implantation, no material was observed by eyes. (4) Pathological examination showed that at 1-3 days after collagen implantation, it was in the stage of acute inflammatory reaction. Cells attached to the material merchant at 5 days. On day 10, vascular structure was formed at the junction of the material and liver. The sinusoid structure of liver was formed in materials at 20-40 days. At 50-60 days, similar hepatic lobule structures could be seen, indicating that the degradation of the material was completed and liver regeneration was basically completed. (5) The results of biological test showed that the hemolysis, epidermal irritation, intradermal irritation, heat source and acute toxicity of collagen of fish scale met the requirements of GB/T16886 Biological Evaluation of Medical Devices. (6) It is concluded that the fish scale collagen extracted by chemical decalcification combined with low temperature enzymatic method has a definite hemostatic effect on bleeding in vivo and on body surface. In vivo degradation time is about 50 days, can provide support for liver regeneration, and is conducive to liver repair.  
    Figures and Tables | References | Related Articles | Metrics
    DNA hydrogel based on drug delivery and bone tissue engineering
    Gao Zhao, Zhao Yuhao, He Yixiang, Zhao Haiyan, Wang Wenji
    2022, 26 (27):  4379-4385.  doi: 10.12307/2022.871
    Abstract ( 725 )   PDF (866KB) ( 279 )   Save
    BACKGROUND: DNA hydrogel has been widely studied because of its many excellent properties, and it provides a good platform for the development of drug delivery and bone tissue engineering, as well as new research and development ideas.
    OBJECTIVE: To review several special types of DNA hydrogels, drug delivery based on DNA hydrogels, and the current development and future prospects of bone tissue engineering. 
    METHODS: A computer-based online search of PubMed, Web of Science, Medline, CNKI and Wanfang databases was performed to retrieve articles regarding DNA Hydrogel based on drug delivery and bone tissue engineering published between January and April 2021 with the search terms of “DNA hydrogel, drug delivery, bone defect, osteogenic differentiation, osteogenic factor”. The types of DNA hydrogels and their applications in drug delivery and bone tissue engineering were retrieved. 
    RESULTS AND CONCLUSION: (1) DNA hydrogel is a hydrophilic polymer network composed of cross-linked DNA chains. As a new type of biological material, it is easy to synthesize and modify sequence programmability, hydrophilicity, stimulus response, biocompatibility, biodegradability, molecular recognition and binding, high entrapment efficiency and so on. (2) At present, the preparation methods of purified and hybrid DNA hydrogels are diversified, which can achieve the targeted delivery of general drugs. Immunotherapy can be achieved through the design of DNA structures such as unmethylated cytosine-phosphate-guanine dinucleotides. (3) As a good carrier of antisense single-stranded nucleotides, DNA hydrogel can be used in gene therapy. (4) In the field of bone tissue engineering, DNA hydrogel can be used as a three-dimensional cell culture site for cell culture. It can promote bone formation and bone tissue vascularization by carrying bone marrow mesenchymal stem cells and osteogenic promoting factor.
    Figures and Tables | References | Related Articles | Metrics
    Application of multicellular construction of vascularized tissue engineered bone in bone repair
    Zhao Doudou, Lin Kaili
    2022, 26 (27):  4386-4392.  doi: 10.12307/2022.872
    Abstract ( 701 )   PDF (1824KB) ( 196 )   Save
    BACKGROUND: Insufficient vascularization of tissue engineered bone is the main challenge that limits the clinical application of bone tissue engineering to repair large bone defects. 
    OBJECTIVE: To summarize the application of bone-forming cells and angiogenic cells to construct tissue engineered bone (based on scaffold or scaffold-free) in bone repair. It is expected to realize the sustainable angiogenesis of tissue engineered bone and the generation of fully functional blood vessels, so as to improve the cell survival rate of bone tissue engineering in the application of large bone defect repair, and to provide a reference for promoting bone formation and remodeling.
    METHODS: The articles published in the CNKI database, PubMed database, and Web of science database from 2000 to 2021 were searched by computer. The Chinese and English key words were “bone tissue engineering, osteogenesis and angiogenesis, multicellular”. According to the inclusion and exclusion criteria, 63 articles were finally included for analysis of the results. 
    RESULTS AND CONCLUSION: (1) At present, the most commonly used bone-forming cells are mainly mesenchymal stem cells, adipose stem cells and osteoblasts, and the most commonly used angiogenic cells are human umbilical vein endothelial cells and endothelial progenitor cells. (2) Encapsulating cells in a scaffold is better than seeding cells on a scaffold in achieving precise positioning of various types of cells. (3) The method of stacking two different mono-cultured cell sheets or co-cultured mono-layered cell sheets can control the position of various types of cells to construct a vascularied network. (4) At present, scaffold-based tissue engineering still needs to overcome the problems of mismatch between scaffold degradation rate and tissue regeneration rate, uncontrollable interaction between cells and biomaterials, and so on. Tissue engineering based on scaffold-free cell sheets needs to overcome the problem of low mechanical strength. (5) The future creation of a functional 3D vascularized tissue engineered bone of clinical size also requires attention, including cell culture and biological mechanisms of action. The combination of tissue engineering, cell engineering and genetic engineering to construct tissue engineered bone is expected to stimulate early angiogenesis, maintain blood circulation, prevent cell death inside the construct, and accelerate the repair of clinical large scale bone defects.
    Figures and Tables | References | Related Articles | Metrics
    Latest research progress and application of bio-printing technology in tracheal tissue engineering
    Pan Ziyin , Lu Yi, Jin Liye, Su Dingwen, Shi Hongcan
    2022, 26 (27):  4393-4400.  doi: 10.12307/2022.873
    Abstract ( 723 )   PDF (871KB) ( 360 )   Save
    BACKGROUND: Long-segmental tracheal lesions are mainly caused by infection, trauma, malignant tumor and other factors, and still cannot obtain satisfactory clinical efficacy. Tracheal tissue engineering combined with bio-printing technology can provide an effective treatment approach for repair of long tracheal injuries.
    OBJECTIVE: To review the application and progress of bio-printing technology in tracheal tissue engineering.
    METHODS: Using the terms “tracheal tissue engineering, 3D printing, 4D printing, bio-inks, tracheal replacement therapy” as key words, relevant articles were searched in CNKI, Wanfang and PubMed databases. The classification of 3D printing technology, design of bio-ink, 4D printing technology and specific applications in tissue engineered trachea were reviewed, and the current deficiencies and future development direction were analyzed.
    RESULTS AND CONCLUSION: The 3D printing technologies applied to tracheal tissue engineering mainly include inkjet, extrusion, sterolithography-based and laser-assisted bio-printing. Each technology has its unique advantages, but still has room for improvement. Bio-inks are an important part of bio-printing, which mainly includes hydrogel, extracellular matrix and scaffold-free bio-ink. Bio-inks need to be compatible with bio-printing technologies, and the printed products need to have appropriate porosity and strong mechanical properties. 4D printing, as an emerging technology which endows 3D printing with the concept of “dynamic and time”, has been altogether applied to tissue-engineered trachea in three targeted regards: epithelialization, cartilage regeneration and revascularization. With the help of bio-printing technology, tracheal grafts can show better biological properties and biocompatibility, constantly moving close to the real clinical application. With the continuous development of bio-printing technology and cross-complementation of modern medical disciplines, more bio-inks and bio-printed tracheae which have excellent biological performance will be developed and gradually applied in clinical practice, so as to solve the medical problem of repairing long-segment trachea defects as early as possible, which bothers the patients throughout the world.
    Figures and Tables | References | Related Articles | Metrics
    Influencing factors and precautions of new vertebral fractures after vertebroplasty for osteoporotic vertebral fractures
    Wang Qian, Dong Junfeng
    2022, 26 (27):  4401-4405.  doi: 10.12307/2022.874
    Abstract ( 604 )   PDF (1338KB) ( 322 )   Save
    BACKGROUND: Vertebroplasty has been widely used in the clinical treatment of osteoporotic vertebral compression fractures, but postoperative vertebral fractures are easy to occur, which reduces the overall efficacy.
    OBJECTIVE: To analyze the influencing factors and precautions of new fracture after vertebroplasty for osteoporotic vertebral compression fracture, so as to guide clinical diagnosis and treatment and prevent new fracture after surgery, which is a common complication.
    METHODS: The first author searched PubMed, CNKI, Wanfang, and VIP databases for new vertebral fractures after vertebroplasty for osteoporotic vertebral compression fractures from 2006 to 2021. The search terms were “osteoporotic vertebral compression fractures, vertebroplasty, new vertebral fractures” in Chinese and English. The authors excluded the articles with low relevance, outdated research content and repeatability, and then made a review.
    RESULTS AND CONCLUSION: The factors that affect new vertebral fractures after vertebroplasty are divided into two categories based on whether they are related to surgery: (1) the patient’s own factors, including age, gender, body mass index, osteoporosis, glucocorticoid use, and mental factors. (2) Factors related to vertebroplasty include kyphosis angle, number of vertebra, intraoperative height of vertebra recovery, cement injection volume, and bone cement extravasation. There are many influencing factors, and the comprehensive findings are mainly divided into osteoporosis, changes in vertebral pressure and changes in vertebral range of motion. It is necessary to carry out targeted prevention and treatment from these three aspects to reduce the incidence of new postoperative fractures and improve the prognosis of patients. The next research direction will be to improve the surgical method and find the bone cement with more suitable strength, better biocompatibility and more convenient filling.
    Figures and Tables | References | Related Articles | Metrics
    Application of the socket-shield technique in the implant restoration
    Wang Wenli, Zhang Zihan, Li Yourui
    2022, 26 (27):  4406-4410.  doi: 10.12307/2022.875
    Abstract ( 591 )   PDF (774KB) ( 496 )   Save
    BACKGROUND: The socket-shield technique can effectively maintain good soft and hard tissue morphology of the immediate planting sites and has a considerable application prospect in the esthetic zone.
    OBJECTIVE: To review the research progress and application of socket-shield technique in implant restoration.
    METHODS: Computers were used to retrieve the PubMed, Web of Science, Wanfang and CNKI databases for relevant literature published from January 2000 to January 2021. The Chinese and English key words were “immediate implant, socket-shield technique, root-membrane technique, root-implant”. Through reading the titles and abstracts, the articles with low correlation and duplication were screened out, and 58 articles were finally included for review and analysis.
    RESULTS AND CONCLUSION: The socket-shield technique is a new method of alveolar ridge preservation, which can effectively maintain the hard and soft tissue morphology of the immediate implant site compared with the traditional method and selectively retain the root slices at different positions in the alveolar fossa according to different clinical conditions. Therefore, it has a considerable application prospect in the implant and restoration of the aesthetic area of anterior teeth. However, the socket-shield technique is sensitive, and the thickness, height and length of the retained root laminae in clinical operation all have an influence on the final restoration effect. In addition, compared with traditional planting, socket-shield technique may have biological complications such as root exposure and root absorption. Thus, it should be used with caution in routine clinical practice until more abundant histological evidence and long-term follow-up data are available.
    Figures and Tables | References | Related Articles | Metrics
    Antibacterial agents loaded on hydroxyapatite scaffolds: action mechanism between the drug and the scaffold
    Xu Ran, Chen Xingyu, Li Zhiqiang
    2022, 26 (27):  4411-4416.  doi: 10.12307/2022.876
    Abstract ( 722 )   PDF (1310KB) ( 278 )   Save
    BACKGROUND: Local infections caused by the implantation of bone repair materials are one of the most serious postoperative complications. It is necessary to improve the effect of the antibacterial agent at the implantation site. 
    OBJECTIVE: To summarize the methods based on hydroxyapatite scaffolds carrying antibacterial drugs, the types of antibacterial drugs, and the mechanism of action between drugs and scaffolds, and summarize the development trend of the drug-loading system. 
    METHODS: The computer used to search the relevant articles included in the CNKI database, PubMed database and Web of Science database. The Chinese and English search terms were “hydroxyapatite, bone tissue engineering, bone repair, bone infection, drug delivery, antibacterial”. Review articles related to hydroxyapatite-based scaffold-loaded antibacterial drugs from January 1997 to January 2021 were involved, including reviews, basic research, and clinical studies. 
    RESULTS AND CONCLUSION: Loading antibacterial drugs on the hydroxyapatite composite scaffold material can effectively increase the local drug concentration, while avoiding systemic toxicity and better promoting bone tissue regeneration. Hydroxyapatite composite scaffold loaded antibacterial drugs have a good drug sustained release effect and anti-infective effect. However, the incorporation of drugs can potentially affect the mechanical properties of calcium phosphate scaffold materials. The current challenge in preparing antibacterial drug delivery systems is to load a sufficient amount of drug molecules while not affecting the mechanical properties of the carrier, while also considering the toxicity of the concentration to cells and tissues. The preparation process of tissue-engineered scaffolds needs to be further improved, and the interaction mechanism between drugs and scaffolds needs further investigation.
    Figures and Tables | References | Related Articles | Metrics
    Novel nano-delivery system: engineered small extracellular vesicles
    Zhang Mi, Wu Saixuan, Dong Ming, Liu Tingjiao, Niu Weidong
    2022, 26 (27):  4417-4422.  doi: 10.12307/2022.877
    Abstract ( 1021 )   PDF (1347KB) ( 274 )   Save
    BACKGROUND: Small extracellular vesicles are often used as an ideal natural endogenous nano-delivery system for drug delivery due to their unique source, structure and physiological function. To overcome the natural limitations of small extracellular vesicles, multiple methods can be used to engineer small extracellular vesicles. 
    OBJECTIVE: To summarize the research status and latest progress of engineered small extracellular vesicles as nano-delivery systems. 
    METHODS: The computer was used to search the related research of engineered small extracellular vesicle and its use as a nano-drug delivery system in databases such as CNKI and PubMed. Chinese key words were “small extracellular vesicles, drug loading, drug delivery”. English key words were “sEVs, engineering exosomes, drug loading, nanopartical delivery system”. The search time limit was from January 2011 to August 2020.
    RESULTS AND CONCLUSION: The engineering methods of small extracellular vesicles mainly include “cell engineering” for parental cells and “small extracellular vesicle engineering” for small extracellular vesicles isolated. Engineered small extracellular vesicle aims to achieve the loading of endogenous and exogenous molecules, drugs, proteins or nucleic acids on the surface or cavity of small extracellular vesicles through surface modification or modification with functional ligands, or to target small extracellular vesicles to the specific types of cells or tissues, improving the delivery performance of small extracellular vesicles from multiple angles and aspects. It has a significant significance in promoting the clinical application of small extracellular vesicles. Engineered small extracellular vesicles have gradually become an important treatment method with broad research prospects in important fields such as cancer treatment, immunotherapy, and regenerative medicine. 
    Figures and Tables | References | Related Articles | Metrics
    Application of drug delivery system in the field of periodontal tissue regeneration
    Zhu Meiying, Jiang Liming, Liu Shuangwei, Ma Mingqi, Yang Yutong
    2022, 26 (27):  4423-4428.  doi: 10.12307/2022.878
    Abstract ( 869 )   PDF (1366KB) ( 2616 )   Save
    BACKGROUND: Local application of growth factors is one of the methods of periodontal tissue regeneration treatment. However, its topical application is limited due to the short half-life of growth factors and their easy dilution and hydrolysis. The drug delivery system can control the release of growth factors so that it can perform biological functions more effectively.  
    OBJECTIVE: To summarize the concept, classification and application of drug delivery system in periodontal tissue regeneration treatment. 
    METHODS: PubMed, CNKI, Wanfang, and VIP databases were searched with the key words of “carrier, drug delivery system, periodontal tissue regeneration, fibers, films, strips, hydrogel, liposome, polymer micelle, microsphere” in English and Chinese, separately. The final 71 articles were included for the review after screening and summarizing in the original 240 articles. 
    RESULTS AND CONCLUSION: The drug delivery system can control the release of growth factors, protect biological activity of growth factors and then promote the repair and regeneration of damaged tissues.  Drug delivery systems can be classified into fibers, films, strips, hydrogel, and microparticulate/nanoparticulate drug delivery system according to the different forms. With the development of pharmacy, polymer material science and periodontology, materials with biocompatibility and biodegradability are gradually used in the research and production of periodontal growth factor sustained-release preparations. That may provide new directions for clinical treatment, but considering the safety of carrier materials, the operability of preparation methods, and the universality of clinical applications, many drug delivery systems used in the field of periodontal regeneration still need to be improved. 
    Figures and Tables | References | Related Articles | Metrics