Repair effects of co-expression of the VEGF and BMP genes via an adeno-associated viral vector on early steroid-in-duced avascular necrosis of the femoral head in rabbits / 中华骨科杂志

ABSTRACT

Objective To investigate the repair effects of co-expression of the VEGF and BMP genes via an adeno-as-sociated viral vector on early steroid-induced avascular necrosis of the femoral head in rabbits. Methords To construct ani-mal model of early SANFH and screen by MRI. The SANFH animal were divided into rAAV-IRES-hrGFP(AAV-GFP), rAAV-hVEGF165-IRES-hrGFP(AAV-VEGF), rAAV-hBMP-7-IRES-hrGFP(AAV-BMP)and rAAV-hVEGF165-IRES-hBMP-7(AAV-VEGF/BMP)groups. The four group virus vectors were injected into core decompression region at the dose of 25μl/site after core decompression operation directly. Repair effects of rAAV vector on early SANFH in rabbits were evaluated by Western blot assay, HE staining, immunohistochemical staining, MRI, radionuclide bone scan, blood vessel counting detected by ink perfusion and fro-zen section, Micro-CT and biomechanical strength detection on the 12th week post-injection. Results Model success ratio was 73.33%. rAAV-hVEGF165-IRES-hBMP-7 virus vector efficiently expressed hVEGF165 and hBMP-7 genes on the 12th week after rAAV injection. hVEGF165 protein secreted in vivo promoted metabolism in core decompression region by increasing the quantity of new vessels and improving the blood supply;hBMP-7 protein secreted in vivo promoted new bone formation in core decompres-sion region by increasing bone mineral density and improving bone biomechanical strength. The AAV-VEGF/BMP group can pro-mote repair effects more effectively than AAV-VEGF group or AAV-BMP group. Conclusion The adeno-associated viral vectors co-expressing hVEGF165 and hBMP-7 can promote repair effects on early SANFH in rabbits by increasing the blood supply and strengthening the bone quality of femoral head.