Matrigel scaffold combined with Ad-hBMP7-transfected chondrocytes improves the repair of rabbit cartilage defect

Abstract

The aim of this study was to explore an effective method for the repair of cartilage defects using chitosan/glycerophosphate (C/GP) gel and Matrigel engineered human bone morphogenetic protein 7 (hBMP7) expressing chondrocytes. Rabbit chondrocytes were obtained, cultured in vitro and transfected with an adenovirus containing hBMP7 and green fluorescent protein (Ad hBMP7 GFP). The expression of hBMP7 in the transfected cells was tested by reverse transcription polymerase chain reaction (RT PCR) and western blotting. The phenotype of the transfected cells was evaluated by detecting the yields of collagen II and hyaluronic acid using RT PCR and enzyme linked immunosorbent assay (ELISA). The growth of chondrocytes in the C/GP gel and Matrigel was accessed by measuring the cell growth rate, hematoxylin and eosin (H&E) staining and observation under a scanning microscope. Twelve adult male New Zealand white rabbits were randomly divided into three groups. Two cartilage defects were created in the rabbits’ knees by aseptic surgery. Group A (n=4) did not receive any treatment, group B (n=4) were treated with C/GP gel and Matrigel engineered Ad mock GFP transfected chondrocytes, and group C (n=4) were treated with C/GP gel and Matrigel engineered Ad hBMP7 GFP transfected chondrocytes. Rabbits were sacrificed at 4 weeks after transplantation, and the repair effect was measured by the Wakitani scoring method. On the basis of the RT PCR and western blot results, hBMP7 was efficiently overexpressed in the Ad hBMP7 GFP transfected chondrocytes. The ELISA results showed that the yields of collagen II and hyaluronic acid in Ad hBMP7 GFP transfected chondrocytes were significantly higher than those in Ad mock GFP transfected chondrocytes. Chondrocytes have a better morphology and arrangement in a Matrigel scaffold than in C/GP, as assessed by H&E staining and scanning microscopy. According to the Wakitani score, Matrigel combined with Ad hBMP7 GFP transfected chondrocytes successfully promoted the repair of cartilage defects in rabbit knees.