OBJECTIVETo investigate the feasibility of repairing bone defect with methods of tissue-engineering and human bone morphogenetic protein-2 (hBMP-2) gene transfection in osteoporotic rats.

METHODSTwenty-four 6-month-old female Sprague-Dawley rats underwent ovariectomy, while 8 rats received sham-operations. Three months later, bone mesenchymal stem cells (BMSC) harvested from osteoporotic rats were divided into two groups randomly. Experimental group were transfected by recombinant plasmid carrying hBMP-2 gene, and control group left untreated. All BMSC were seeded into coralhydroxyapatite scaffolds. Then the cell/scaffold constructs were implanted into the defect site created in the ramus of mandible of osteoporotic rats respectively.

RESULTSPositive results were confirmed by immunohistochemistry and in situ hybridization in experimental group. New bone formation was found at the margin of the defect treated with the BMSC modified by hBMP-2 gene transfer at 4 weeks after implantation and appeared mature 8 weeks after the treatment. However, the amount of newly formed bone was much less and there was some adipose tissue at defect margins 8 weeks after implantation in control group.

CONCLUSIONSThe results of this experiment indicate that BMSC-mediated rhBMP-2 gene therapy in conjunction with bone tissue engineering may allow for successful treatment of large bone defects in osteoporosis rats.