The construction of vascularized artificial bone in vitro and ectopicosteogenesis in vivo

Objectives: To investigate the method of constructing vascularized artificial bone in vitro and Ectopic osteogenesis in vivo. Methods: To dissociate and culture rat bone marrow mesenchymal stem cells and kidney vascular endothelial cells, and analyse osteogenesis ability of bone marrow mesenchymal stem cells in different co-culture models(co-culture with or without direct contact) by measuring the quantity of protein and the activity of Alkaline phosphatase and osteocalcin. By establishing the three-dimensional co-culture model of rat bone marrow mesenchymal stem cells and kidney vascular endothelial cells , we constructed vascularized artificial bone, then implanted it into the muscle of rats. By soft X-ray examination and HE staining , we observed the osteogenetic ability of the implants. Results:In the direct and indirect co-culture groups of rat bone marrow mesenchymal stem cells and kidney vascular endothelial cells and simple culture group of marrow mesenchymal stem cell, the ALP activity was 0.625Êz0.223 U/mg°¢0.412Êz0.178 U/mg°¢0.141Êz0.08 U/mg; osteocalcin was 0.8Êz£°.124µg/L°¢0.435Êz0.216µg/L°¢0.235Êz0.146µg/L. Statistical analysis showed that the osteogenetic ability of bone marrow mesenchymal stem cells co-cultured was higher than that of simple cultured(P<0.05), and the osteogenetic ability of direct co-cultured cells was higher than that of indirect co-cultured(P<0.05).The expeiment in vivo manifested that the intensity of soft X-ray and the quantity of vascular and new formed bone in vascularized artificial bone group were higher than those in the contrast group(P<0.05). Conclusions: The osteogenetic ability of bone marrow mesenchymal stem cells can be regulated by cytokines and cell membrane proteins when co-cultured with endothelial cells. Compared with traditional artificial bone, vascularized artificial bone has lots of advantages, such as accelerating the differentiation, the proliferation and the osteogenesis ability of bone marrow mesenchymal stem cell, increasing local blood circulation and survive ratio, accelerating osteogenesis and having more powerdul anti-infect ability.