2022, Vol. 26 ›› Issue (29): 4638-4642

Effects of total flavonoids of Rhizoma drynariae on bone remodeling and expression of bone morphogenetic protein-2, vascular endothelial growth factor and CD31

Zhao Dun1, Fang Bin2, Yi Chunzhi2, He Mincong2, Zheng Jiaqian1, Li Yue2   

Abstract: BACKGROUND: Numerous studies have shown that the total flavonoids of Rhizoma drynariae can promote bone healing, but the specific molecular mechanism is still unclear.
OBJECTIVE: To investigate the effect of total flavones of Rhizoma drynariae on bone remodeling after bone defects.
METHODS: Thirty-six male Sprague-Dawley rats were randomly divided into three groups (n=12 per group): blank group, induced membrane group, induced membrane+traditional Chinese medicine group). After a 4-mm bone tissue sample was taken from the middle part of the right femur of each rat, the femur was fixed with a steel plate and inserted with polymethylmethacrylatebone cement. Four weeks after fixation, the second operation was performed to remove the previously detached bone cement. The blank group did not receive bone graft, and the induced membrane group and the induced membrane+Chinese medicine group received autologous coccyx bone graft. Afterwards, the induction membrane+traditional Chinese medicine group was given the total flavonoids of Rhizoma drynariae 0.22 g/(kg•d) by gavage, and the other two groups were given the same amount of normal saline by gavage. Six weeks after bone grafting, X-ray and histomorphological examinations were performed to observe the formation of new bone tissue in the defect area. Immunohistochemistry staining was used to detect the protein expressions of bone morphogenetic protein 2, vascular endothelial growth factor, and CD31 (platelet-endothelial cell adhesion molecule) in bone tissue.       
RESULTS AND CONCLUSION: X-ray films indicated that there was continuous bone tissue in the bone defect area, the medullary cavity was formed, and the bone cortex was reconstructed well in the induced membrane+traditional Chinese medicine group; the induced membrane group did not form a complete cortical bone, in which the medullary cavity was not completely formed and no continuous bone tissue formed; the bone defect area in the blank group was still visible. Histomorphological observations indicated that there was no continuous bone formation in the defect area of the blank group, while new bone tissue was formed to different extent in the defect area of the other two groups. The induced membrane+traditional Chinese medicine group was in the stage of bone shaping. In the induced membrane group, new bone tissue formed unevenly and there was still inflammatory cell infiltration and connective tissue hyperplasia in the defect area. Immunohistochemical findings revealed that the protein expression of bone morphogenetic protein-2 and vascular endothelial growth factor was significantly higher in the induced membrane+traditional Chinese medicine group than the other two groups (P < 0.05), while the protein expression of CD31 was significantly higher in the induced membrane+traditional Chinese medicine group than the blank group (P < 0.05). To conclude, total flavones of Rhizoma drynariae can regulate the expression of bone morphogenetic protein-2 and vascular endothelial growth factor proteins and promote bone mineralization and remodleing in the bone defect area.
Key words: induced membrane, Masquelet technique, total flavones of Rhizoma drynariae, bone defect, bone remodeling, bone morphogenetic protein-2, vascular endothelial growth factor, CD31