Chinese Journal of Tissue Engineering Research ›› 2025, Vol. 29 ›› Issue (6): 1168-1175.doi: 10.12307/2025.325

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Epidural fibrous scar formation in rabbits following autologous ligamentum flavum intervention 

Zhang Debao1, Wang Peng1, Li Kun2, Zhang Shaojie2, Li Zhijun2, Li Shuwen1, Wu Yimin1   

  1. 1Center for Spine Surgery, Second Affiliated Hospital, Inner Mongolia Medical University, Hohhot 010000, Inner Mongolia Autonomous Region, China; 2Anatomy Teaching and Research Department, Inner Mongolia Medical University, Hohhot 010000, Inner Mongolia Autonomous Region, China
  • Received:2024-02-23 Accepted:2024-04-09 Online:2025-02-28 Published:2024-06-21
  • Contact: Li Shuwen, Professor, Master’s supervisor, Center for Spine Surgery, Second Affiliated Hospital, Inner Mongolia Medical University, Hohhot 010000, Inner Mongolia Autonomous Region, China Co-corresponding author: Wu Yimin, Professor, Master’s supervisor, Center for Spine Surgery, Second Affiliated Hospital, Inner Mongolia Medical University, Hohhot 010000, Inner Mongolia Autonomous Region, China
  • About author:Zhang Debao, Master, Center for Spine Surgery, Second Affiliated Hospital, Inner Mongolia Medical University, Hohhot 010000, Inner Mongolia Autonomous Region, China Wang Peng, Master candidate, Center for Spine Surgery, Second Affiliated Hospital, Inner Mongolia Medical University, Hohhot 010000, Inner Mongolia Autonomous Region, China Zhang Debao and Wang Peng contributed equally to this work.
  • Supported by:
    the Natural Science Foundation of Inner Mongolia Autonomous Region, No. 2022MS08019 (to LSW); General Scientific Research Project of Inner Mongolia Medical University, No. YKD2021MS010 (to LSW) 

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Abstract:
BACKGROUND: It has been proved clinically that adhesion of fibrous scar with the dura mater or nerve root after lumbar operation is an important factor for postoperative symptoms, such as postoperative pain and numbness. 
OBJECTIVE: To verify the inhibitory effect of autologous ligamentum flavum on the formation of epidural fibrous scar after lumbar surgery and explore the possible molecular biological mechanism.
METHODS: Forty-eight Japanese white rabbits (6-8 months old) were randomly divided into three groups: a ligamentum flavum preservation group, a ligamentum flavum non-preservation group, and an autologous fat reposition group. A lumbar laminectomy model was established in all the three groups of rabbits, and rabbit epidural tissues were collected at 3 and 6 weeks after modeling. Hematoxylin-eosin staining was used to observe histological changes and the number and density of fibroblasts, VG staining was used to observe the percentage of collagen fiber area, and immunohistochemistry was used to observe the expression of transforming growth factor β1 and Smad3 proteins. 
RESULTS AND CONCLUSION: Hematoxylin-eosin staining results revealed that fibroblasts in the ligamentum flavum preservation group were few and loosely arranged, while the cells in the ligamentum flavum non-preservation and autologous fat reposition groups were more numerous and closely arranged. The number density of fibroblasts in the ligamentum flavum preservation group was lower than that in the ligamentum flavum non-preservation and autologous fat reposition groups at 3 and 6 weeks after surgery (P < 0.05); however, there was no significant difference between the latter two groups. VG staining results showed that the collagen fibers in the ligamentum flavum preservation group were sparse and distributed unevenly, while a lot of red collagen fibers were gathered in the ligamentum flavum non-preservation and autologous fat reposition groups. The area percentage of collagen fibers in the ligamentum flavum preservation group was lower than that in the ligamentum flavum non-preservation and autologous fat reposition groups at 3 and 6 weeks after surgery (P < 0.05), but there was no significant difference between the latter two groups. The results of immunohistochemistry showed that the degree of positive staining of retained histone the ligamentum flavum preservation group was significantly lower than that of the other two groups. The absorbance value of transforming growth factor β1 and Smad3 in the ligamentum flavum preservation group was significantly lower than that in the other two groups at 3 and 6 weeks after surgery (P < 0.05), but there was no significant difference between the latter two groups. To conclude, there are different degrees of epidural fibrous scar formation after lumbar surgery. If the ligamentum flavum is preserved, it can help to reduce the number of epidural fibroblasts as well as the formation of collagen fibers, thus reducing the adhesion of the fibrous scar tissue to the dural sac and nerve root. The mechanism is not only a purely mechanical blockade, but also to reduce the formation of epidural fibrous scar by interfering with the transforming growth factor β1/Smad3 signaling pathway.

Key words: lumbar spine, ligamentum flavum, fibrous scar, TGF-β1/Smad3, signaling pathway, fibroblast, rabbit

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