Theaflavin-3-gallate modified nano-hydroxyapatite/ polycaprolactone composite porous scaffold in bone defect repair
Liu Ming, Wang Kai
First Department of Orthopedics, Qinghai Provincial People’s Hospital, Xining 810000, Qinghai Province, China
Abstract: BACKGROUND: Theaflavin-3-gallate (TF-3G) can significantly inhibit bone resorption and has obvious effects on preventing osteoporosis, but its application on osteogenesis is rare.
OBJECTIVE: TF-3G was loaded into nano-hydroxyapatite/polycaprolactone composite scaffold to observe its osteogenic effect.
METHODS: TF-3G solution of different mass concentrations was prepared. The cytotoxicity of TF-3G was detected by CCK-8 assay. According to cytotoxicity test results, bone marrow mesenchymal stem cells were intervened by TF-3G solution of appropriate mass concentration (0, 0.86, 4.30, 8.60, 17.20, 34.4, 68.8, 86, 106 mg/L). CCK-8 assay was used to detect its proliferative activity during osteogenic differentiation. A certain concentration of TF-3G solution was selected to induce bone marrow mesenchymal stem cells to differentiate towards osteogenic direction, and alkaline phosphatase activity detection and alizarin red staining were performed. Nano-hydroxyapatite/polycaprolactone composite porous scaffold was prepared using selective laser sintering rapid prototyping technology. TF-3G was loaded into nano-hydroxyapatite/polycaprolactone composite porous scaffold by solution impregnation and freeze-drying. A 1.5 cm bone defect was made in the radius of adult New Zealand white rabbits. The blank control group was not implanted with any material. The two experimental groups were implanted with nano-hydroxyapatite/polycaprolactone, and TF-3G/nano-hydroxyapatite/polycaprolactone composite porous scaffold. The imaging examination and histological observation were performed after operation.
RESULTS AND CONCLUSION: (1) CCK-8 assay showed that 0.86, 4.30, 8.60 mg/L TF-3G promoted the proliferation of bone marrow mesenchymal stem cells; 17.20, 34.4, 68.8, 86, 106 mg/L TF-3G inhibited the proliferation of bone marrow mesenchymal stem cells; 0.86, 4.30, 8.60 mg/L mass concentration was chosen for osteoinduction experiment. (2) Alkaline phosphatase activity detection and alizarin red staining showed that with the increased mass concentration of TF-3G solution, the bone formation effect was enhanced. (3) Lane-Sandhu X-ray scores at 4 and 12 weeks after operation in the two experimental groups were higher than those in the blank control group (P < 0.05), and the scores were higher in the TF-3G/nano-hydroxyapatite/polycaprolactone group than those in the nano-hydroxyapatite/polycaprolactone group (P < 0.05). (4) At 12 weeks after operation, combined with the results of hematoxylin-eosin staining and Masson staining, Huddleston histological score of the two experimental groups was higher than that of the blank control group (P < 0.05), and the score in the TF-3G/nano-hydroxyapatite/polycaprolactone group was higher than that of the nano-hydroxyapatite/polycaprolactone group (P < 0.05). (5) Results concluded that TF-3G can promote the proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells. Nano-hydroxyapatite/polycaprolactone composite porous scaffold loaded with TF-3G can promote the repair of bone defects.
Key words: theaflavin, theaflavin-3-gallate, nano-hydroxyapatite, polycaprolactone, scaffold, bone defect, bone repair