Experimental Research Of Reparing Rabbit Femoral Head Osteonecrosis With Vascularized P-DL-LA/nHA Porous Scaffold

Objective Steroid induced osteonecrosis of femoral head is common clinical disease,its pathological mechanism is still not fully understood,this experiment try to create a rabbit osteonecrosis model which pathological symptoms is close to clinical osteonecrosis by a combination application of lipopolysaccharide and methylprednisolone.The efficiency and feasibility will be discussed.Materials and Methods 36 rabbits were randomly divided into 4 groups:group A to D used only LPS,LPS and MPS,only MPS and control group respectively.All animals were taken blood tests,imaging detection and histological tests 6 weeks after a last injection of LPS or MPS.Results Histological results showed a total osteonecrosis rate was 83.3%(25/30),the most frequent parts of osteonecrosis is metaphysic,the osteonecrosis was well demarcated,ashcolored and irregularly shaped,the necrotic area showed an accumulation of cell debris,a disappearance of fat cells and bone marrow.Blood platelet levels was significantly decreased in B group than group A and C. Magnetic resonance imaging showed each tl-weighted images in femoral and proximal femoral performance for a patch or flake low signal, the t2-weighted images show high signal for irregular sheets, Micro-CT shows trabeculae sparse in necrotic area, dense or vacuoles, cartilage surface thins, irregular shape.Conclusions Combined application of LPS and MPS can effectively induce osteonecrosis of femoral head,the animal model had similar pathology symptoms as human osteonecrosis,this approach is efficient.Objective Try to separate and cultivate BMSCs,and induce them to vascular endothelial cells,seeded the endothelial cells as seed cells in PDLLA/nHA scaffold,cultivated the cells/scaffold complex,observed the biocompatibility,scaffold ultrastructue by SEM,observed the vascular induction ability in vivo.Materials and Methods The results of flow cytometry showed that immunophenotype of the induced cells were CD31+, CD34+, VEGFR-2+/CD45-, CD105-,confirmed for vascular endothelial cells.The PDLLA/nHA scaffolds had a good biocompatibility with BMSECs,for ultrastructure it had a moderate pore,good connectivity.After 2 weeks implantation the cell/scaffold induced apparent capillary structures.Conclusions Bone marrow stem cells can be induced into vascular endothelial cells,and can be used as seed cells implant in PDLLA/nHA scaffold,the cell/scaffold complex had a good biocompatibility,and good vascular induction ability in vivo.Objective Try to repair a rabbit osteonecrosis of femoral head with a vascularized PDLLA/nHA scaffold fabricated in vitro. Materials and Methods Induced a rabbit femoral head osteonecrosis model by a combination application of LPS and MPS.All animal models were first taken a core decompression,then divided randomly into 3 groups,group A was implanted a BMSECs/PDLLA/nHA scaffold,group B was implanted a PDLLA/nHA scaffold,and group C was control group.Blood samples were collected for osteocalcin detection by ELISA.MRI were taken for imaging analysis,Micro-CT were performed for bone structure and vascular system,HE stain and VWF immunohistochemistry were taken for histological analysis.Results Blood osteocalcin in group A were significantly higher than other 2 groups;MRI and Micro-CT images showed a obvious new bone formation and tissue repairing in gourp A,VVF and BVF detected by Micor-CT in group A were higher than other 2 groups,histological analysis showed MVD in group A were higher than other 2 groups,and more bone marrow cells and mineralization matrix were seen.Conclusion Implanting a vasularized PDLLA/nHA scaffold combined with core decompression may represent a promising approach for early stage femoral head osteonecrosis.