Expression of vascular endothelial growth factor in osteonecrosis of the femoral head during the repairing with biodegradable strontium-doped calcium polyphosphate / 中国矫形外科杂志

ABSTRACT

[Objective]To investgate the expression of vascular endothelial growth factor in osteonecrosis of the femoral head during the repairing with biodegradable strontium-doped calcium polyphosphate in glucocorticoid-induced rabbits.[Method]Twenty mg/kg methylprednisolone was injected into right gluteus medius muscle at intervals of 24 hours for three times in 21 adult male Japanese white rabbits.Three rabbits were killed randomly at 2 weeks after methylpednisolone injection,both the femora and humeri were histologically examined for the presence of osteonecrosis. The remaining 18 animals with a total of 36 cylindrical 2.5?5 mm femoral head defects were created following the trapdoor procedure. Eighteen animals with femoral head bone defects were randomly divided into three groups. Group A:the defects filled with strontium-doped calcium polyphosphat,Group B:the defects filled with calcium polyphosphate and Group C:the defects filled with autologous cancellous bone alone. Roentgenographic and histological examinations were performed postoperatively. Finally,immunohistochemical analysis using monoclonal antibodies anti-VEGF was performed.[Result]No hip joint dislocation occurred. In Group A,the results of VEGF expression had a significantly difference from those in the other groups 12 weeks after operation. Most of the biodegradable strontium-doped calcium polyphosphate was resorbed and was largely replaced by newly formed trabecular bone at 12 weeks. While in Group B,a major part of defect were repaired. New formed trabecular bone in the defect was very thin. In Group C,morsellized cancellous bone was completely surrounded by fibrous and newly formed trabecular bone. [Conclusion]VEGF expression in the defect of osteonecrosis of the femoral head during the repairing with biodegradable strontium-doped calcium polyphosphate may play a role in stimulating vascular invasion and granulation tissue formation.This may be an important step toward facilitating the resorption in the osteonecrosis,thus impooring the repairing proceduce of femoral head defect.