Experimental Study On The Repair Of Ad-BMP-2/BMSCs/DBM For Rabbits’ Femoral Head Necrosis

Objective: Evaluate the effect of the Adenovirus-Bone Morphogenetic Protein-2/Bone Mesenchymal Stem Cells/Demineralized Bone Matrix,(Ad-BMP-2/BMSCs/DB)for rabbits’ femoral head necrosis and explore the new treatments for femoral head necrosis. Methods:(1) Prepare femoral head necrosis models by clinical core decompression combined with liquid nitrogen frozen.(2) After built models, animals were randomly devided into 4 groups(n=12) as follows: group A was not implanted anything as control group, group B was implanted into DBM, group C was implanted into hBMP-2/DBM, group D was implanted into hBMP-2/BMSCs/DBM.(3) Four rabbits of each group were killed at 4,8,12, weeks after surgery. Detected the X-ray manifestations, bone repair score, gross specimen repair, trabecular bone structure, BMP-2 gene expression, surface morphology and the ratio of calcium and phosphorus(Ca/P) through X-Ray technique、Lane-Sandhu score、gross specimen observation 、 Hematoxylin-Eosin staining(HE) 、 Inverted microscopy 、 Polymerase Chain Reaction(PCR) 、 Scanning Electron Microscope(SEM)、Energy Dispersive Spectroscopy(EDS). And then evaluate the rehabilitation effect of the necrotic femoral head through these results. Results: X-ray showed: In group A the defect area of femoral head was still clear. There are a little fibrous hyperplasia and no obvious osteogenic response. The femoral head defect areas of group B、group C and group D became fuzzy, and there were new bone trabeculars, but the regenerate phenomenons of group D were significantly better than that of the same time group B and group C. The Lane-Sandhu X-Ray scores showed: group A<group B and group C<group D(P<0.05). The observation of the specimen showed: the femoral head of group A collapseed and there were some drilling holes. The femoral heads of group B and group C had no collapsein and the drilling holes still existsed. The femoral head of group D had no collapsein and the drilling holes disappered. HE staining showed that in group A bone trabeculars became necrotic and fragmented and there were a lot of air trapped cells. There were newborn immature bone trabeculars and osteoblasts in group B and group C. Group D had large number of bone cells, fat cells, and newborn mature bone trabeculars. The ratio of empty lacuna showed: group A> group B and group C > group D(P<0.05). The RT-PCR showed: the expression of BMP-2 in group A < group B < group C < group D(P<0.05). SEM showed: there were no calcific depositions in group A.Group B and group C had some calcific depositions and low calcific bone. There were new mature bone in group D and there were no obvious difference comparing with the normal bone tissue. EDS showed: The Ca/P of group A < group B < group C < group D and there was no significant difference between group D and normal femoral head. Conclusions: After implanting BMP-2/BMSCs/DBM in vivo, it can induce BMSCs to differentiate into osteoblasts. This has a good repairing effect on rabbits with avascular necrosis of the femoral head. It shows a good applicational prospect in the treatment of avascular necrosis of the femoral head.