Abstract: BACKGROUND: Naringin has been shown to promote the proliferation and osteogenic differentiation of bone marrow derived mesenchymal stem cells, making it a potential candidate for treating osteoporosis andenhancing fracture healing. However, its clinical application is limited by its low bioavailability.
OBJECTIVE: To prepare chitosan/β-tricalcium phosphate scaffolds loaded with naringin and characterize their biological properties.
METHODS: Chitosan/β-tricalcium phosphate scaffolds were prepared by freeze-drying and chemical crosslinking. The chitosan/β-tricalcium phosphate scaffolds were immersed in anhydrous ethanol solution containing naringin for 3 hours. After vacuum cold drying, chitosan/β-tricalcium phosphate/naringin scaffolds were obtained. The pore size, porosity, swelling rate, degradation rate, mechanical properties, and in vitro release capacity of naringin of the scaffolds were characterized. Rat bone marrow mesenchymal stem cells were inoculated on the surface of chitosan/β-tricalcium phosphate scaffolds and chitosan/β-tricalcium phosphate/naringin scaffolds, respectively, and cell proliferation, adhesion, activity and alkaline phosphatase activity after osteogenic differentiation were detected.
RESULTS AND CONCLUSION: (1) The results of scanning electron microscopy showed that the naringin-chitosan/β-tricalcium phosphate composite scaffold had a porous mesh structure. The average pore diameter was (106.82±25.22) μm; the porosity was (76.26±4.81)%; 24-hour swelling rate was (796.17±31.76)%; in vitro degradation rate of 7.71% at 4 weeks, and naringin could be slowly released in vitro for 9 days. There was no significant difference in the average pore size, porosity, 24-hour swelling rate, in vitro degradation rate, compression strength and compression modulus at 4 weeks between the chitosan/β-tricalcium phosphate scaffold and the chitosan/β-tricalcium phosphate scaffold (P > 0.05). (2) Rat bone marrow mesenchymal stem cells adhered well to the surfaces of the two scaffolds and had good activity. Compared with the chitosan/β-tricalcium phosphate scaffold, the chitosan/β-tricalcium phosphate/naringin scaffold promoted the proliferation of rat bone marrow mesenchymal stem cells (P < 0.05), and increased the alkaline phosphatase activity of bone marrow mesenchymal stem cells after osteogenic differentiation (P < 0.05). (3) The results show that the chitosan/β-tricalcium phosphate/naringin scaffolds exhibit favorable physical properties and can effectively promote the adhesion, proliferation, and osteogenic differentiation of bone marrow-derived mesenchymal stem cells. 

Key words: naringin, chitosan, β-tricalcium phosphate, scaffold, bone defect repair, bone tissue engineering, engineered bone materials