Experimental Study Of Construction Of Tissue Engineered Gel Induced Vascularization In Osteonecrosis In Vivo

Partâ… An optimization method for the Isolation, cultivation, and characterization of aortic endothelial cells from rabbitBACKGROUND:Vascular endothelial cells (VECs) have the ability to enhance production of new blood vessels and provide nutrition for the bone tissue regeneration.OBJECTIVE:Providing seed cells for the vascularization of bone tissue engineering.METHODS:Processing includes intimal eversion and collagenase digestion, endothelial cells (ECs) harvested from rabbit aorta were isolated and cultured and passaged. ECs were identified by inverted microscope, transmission electron microscopy and immunofluorescence.RESULTS:The cells displayed the typical endothelial phenotype of closely opposed polygonal cells with very clear and well-defined cell border (cobble- stone appearance). ECs identitied as Weibel-Palade bodies in transmission electron microscopy and showed CD31 (+) in immunofluorescence.CONCLUSION:We obtained a good cellular activity with a high purity using a new and easy method. The cells displayed a high cellular yield and proliferation. these cells can be used for the vascularization of bone tissue engineering. Partâ…¡A rabbit model of femoral head necrosis induced by intraosseous injection of pure alcoholBACKGROUND:Osteonecrosis of the femoral head (ONFH) is diagnosed with increasing periodicity in young adults and is a disease with a significant high disability. There is no dependable animal model of ONFH for the evaluation of new therapeutic means.OBJECTIVE:This study was to develop an animal model, which allows the evaluation of different therapeutic approaches.METHODS:Pure alcohol was injected into the centre of the femoral head in New Zealand white rabbits under fluoroscopic control. After 2,4 and 6 weeks the animals were killed and the femoral heads were harvested. Radiographic, magnetic resonance imaging (MRI) and histological changes were analysed and recorded.RESULTS:Partial osteonecrosis was confirmed over a period of 6 weeks in all animals. The morphology of necrosis in combination with intact macrotexture and joint cartilage is similar to the features described in early ONFH in humans.CONCLUSION:We obtained a good efficacy and similarity animal model of the early stages of ONFH in humans. this model may be compatible to develop new therapeutic methods for ONFH. Partâ…¢Experimental study of tissue-engineered gel induced vascularization in osteonecrosis of femoral headBACKGROUND:Avascular necrosis of the femoral head is a painful disorder of the hip that can lead to collapse of the femoral head and the need for total hip replacement following joint destruction. Early treatment of this disease still remains a clinical challenge.OBJECTIVE:Endothelial and smooth muscle cells (EC/SMC) have been demonstrated to contribute to vasculogenesis and osteogenesis in animal models in vivo. We hypothesized and proved that the transplantation of EC/SMC could have a role for prevention of osteonecrosis by promoting vasculogenesis and osteogenesis.METHODS:Alcohol-induced osteonecrosis of the femoral head was developed in rabbits and we then administered tissue-engineered collagen gels contain EC/SMC and microspheres by intraosseous injection. We produced Polymer microparticles that deliver VEGF and MCP-1 with distinct release kinetics and that can be integrated into a collagen gels construct for delivery of EC/SMC. At 2,4,6 weeks, after administration, the vasculogenesis and osteogenesis of the femoral head were evaluated with radiograph and magnetic resonance imaging in morphometry, haematoxylin eosin (H&E) staining and immunohistochemistry in histology. Using the Image-Pro Plus image analysis software to analyze microvessel density, neovascularization in diameter and the number of coated smooth muscle cells of mature neovascularization. Statistical significance was determined using Two-sample t-test. P values of less than 0.05 were considered significant.RESULTS:X-ray, MRI and histopathological showed the area of bone necrosis decreased, new capillaries and new bone repaired the necrotic area. Immunohistochemistry showed a-SMA (+) blood vessel formation. There was a trend towards an increase in vessel density, mean vessel diameter and mature vessel associated with delivery of tissue-engineered collagen gels contain EC/SMC and microspheres, only the combination therapy group yielded a statistically significant increase in vessel density compared to other groups.CONCLUSION:We show here that a network of stable and functional blood vessels can be formed in rabbits by co-implantation of EC/SMC and demonstrated the potential of EC /SMC in therapeutic vascularization. The new therapeutic approach with tissue-engineered collagen gels could be a promising therapy for early-stage osteonecrosis of the femoral head.