Transplantation of combined endothelial progenitor cells and bone marrow mesenchymal stem cells for femoral head necrosis in rabbits

Objective To promote the osteogenesis and angiogenesis by transplanting endothelial progenitor cells（EPCs） and bone marrow mesenchymal stem cells（BMSCs） into the femoral head necrotic zone. Methods BMSCs and EPCs, isolated from rabbit bone marrow by density gradient centrifugation were cultured. Their alkaline phosphatase（ALP） activity was assayed for the determination of their best ratio. The cultured BMSCs and EPCs that were transplanted into the rabbit model of necrotic femoral head were divided into BMSCs transplantation group（group A）, EPCs transplantation group（group B）, BMSCs and EPCs transplantation group（group C）. Osteogenesis and angiogenesis in the rabbit model of necrotic femoral head were observed at week 4 after operation. Results The best ratio of co-cultured EPCs and BMSCs was 1∶1. The BMP-2 protein expression level was higher and more new blood vessels were formed in group C than in group A and B（P＜0.05）. Histology showed bone-like tissue in group A, vascular structure in group B with less bone-like tissue, and vascular structure and bone-like tissue in group C. Conclusion Transplantation of EPCs and BMSCs into femoral head necrotic zone at the ratio of 1∶1 can effectively promote the osteogenesis and angiogenesis.