Application of tissue-engineered cartilage with BMP-7 gene to repair knee joint cartilage injury in rabbits.

Injured articular cartilage has a poor capacity for spontaneous healing. So far, satisfactory solution to this subsistent problem has not been found, but transgenic therapy may be a promising way. This study aims to evaluate the effectiveness of a tissue-engineered cartilage that was transfected with morphogenetic protein 7 (BMP 7) in repairing the cartilaginous defects of rabbit knee joints. Chondrocytes were transfected with BMP-7 gene (5 x 10(6) cells/ml), inoculated into the collagen-fibrin gel scaffolds, and cultured for 14 days. Then, the scaffolds were implanted onto the created defects (5.0 mm in diameter) in rabbits' knee joints. After 12 weeks, the rabbits were sacrificed and histological sections were evaluated using modified O'Driscoll cartilage scores; In situ hybridization and immunohistochemistry were performed to detect the expression of BMP-7 mRNA and BMP-7 at the implanted site while the content of DNA and GAG was determined as well. A better quality of repairs was observed at the 12th week after implantation when compared to the control group using histological analyses. The content of DNA and specific secretion of GAG in the treatment group is statistically significant different compared with the control group. Gene therapy may be a promising treatment method, but the novel therapy approach needs further studies with respect to a longer follow-up period.