BackgroundThis study was designed to investigate the effect of BMSCs transfected BMP-2 composite with magnesium alloy rod in the repair of the femoral head necrosis in New Zealand white rabbits. Multifactorial but mostly traumatic, osteonecrosis of the femoral head account for 10 % of the 250,000 total hip arthroplasties done annually in the United States while its prevalence in most countries in not known. However, early intervention prior to collapse is critical to successful outcomes in joint preserving procedures.MethodsThe pcDNA3.1 plasmid from cultured BMSCs was successfully transfected into BMSCs-BMP-2 by electroporation. Femoral head necrosis were established in 40 rabbits by liquid nitrogen freezing method. Animals were randomly divided into four groups (n = 10): Mg rod/BMSCs group, Mg rod group, BMSCs group, and blank control group. The composite of BMSCs-BMP-2 on Mg alloy rods were implanted respectively into the left femoral metaphysis of rabbits till the femoral head. Radiographic X-ray examination, histological hematoxilin and eosin (H&E) analysis and immunohistochemistry techniques were performed postoperatively; to observe and compare by the schedule; the newly formed bone and the degradation of the Mg rod at 6 and 12 weeks, sacrificing five animals at each time.ResultsTwelfth week histological and immunohistochemical examinations showed complete magnesium alloy absorption in experimental and control group. H&E staining and immunohistochemistry showed obvious differences, Mg rod/BMSCs group having the best recovery than the other groups. BPM-2 level of gene expression of experimental group was also higher than those of controlled group.ConclusionBMP-2 coated Mg alloy promotes the expression of bone growth factors at the implant in marrow of rabbits thus delaying femoral head necrosis and improving repair.

A chemically extracted acellular allogeneic nerve graft can reduce postoperative immune rejection, similar to an autologous nerve graft, and can guide neural regeneration. However, it remains poorly understood whether a chemically extracted acellular allogeneic nerve graft combined with neurotrophic factors provides a good local environment for neural regeneration. This study investigated the repair of injured rat sciatic nerve using a chemically extracted acellular allogeneic nerve graft combined with ciliary neurotrophic factor. An autologous nerve anastomosis group and a chemical acellular allogeneic nerve bridging group were prepared as controls. At 8 weeks after repair, sciatic functional index, evoked potential amplitude of the soleus muscle, triceps wet weight recovery rate, total number of myelinated nerve fibers and myelin sheath thickness were measured. For these indices, values in the three groups showed the autologous nerve anastomosis group > chemically extracted acellular nerve graft + ciliary neurotrophic factor group > chemical acellular allogeneic nerve bridging group. These results suggest that chemically extracted acellular nerve grafts combined with ciliary neurotrophic factor can repair sciatic nerve defects, and that this repair is inferior to autologous nerve anastomosis, but superior to chemically extracted acellular allogeneic nerve bridging alone.