IGF‐1 and BMP‐7 synergistically stimulate articular cartilage repairing in the rabbit knees by improving chondrogenic differentiation of bone‐marrow mesenchymal stem cells

Knee injury is known as a frequently occurred damage related to sports, which may affect the function of cartilage. This study aims to explore whether Insulin‐like growth factor 1 (IGF‐1) and bone morphogenetic protein‐7 (BMP‐7)‐modified bone‐marrow mesenchymal stem cells (BMSCs) affect the repair of cartilage damage found in the knee. Primarily, BMSCs were treated with a series of pEGFP‐C1, IGF‐1, and BMP‐7, followed by determination of IGF‐1 and BMP‐7 expression. A rabbit cartilage defect model was also established. Afterfward, cell morphology, viability, cartilage damage repair effect, and expression of collagen I and collagen II at the 6th and the 12th week were measured. BMSCs treated with pEGFP‐C1/IGF‐1, pEGFP‐C1/BMP‐7, and pEGFP‐C1/BMP‐7‐IGF‐1 exhibited elevated expression of BMP‐7 and IGF‐1. Besides, BMSCs in the P10 generation displayed decreased cell proliferation. Moreover, BMSCs treated with IGF‐1, BMP‐7, and IGF‐1‐BMP‐7 showed reduced histological score and collagen I expression while elevated collagen II expression, as well as better repair effect, especially in those treated with IGF‐1‐BMP‐7. Collectively, these results demonstrated a synergistic effect of IGF‐1 and BMP‐7 on the BMSC chondrogenic differentiation on the articular cartilage damage repair in the rabbit knees, highlighting its therapeutic potential for the treatment of articular cartilage damage. These results demonstrate that IGF‐1 and BMP‐7 gene modification may contribute to the repair of cartilage damage in the knee by BMSCs.