Local intra-articular injection of vascular endothelial growth factor accelerates articular cartilage degeneration in rat osteoarthritis model

In the pathophysiology of osteoarthritis (OA), articular cartilage degeneration exhibits a significant role. Vascular endothelial growth factor (VEGF) is considered to be an effective angiogenic factor and a crucial regulator of articular cartilage degeneration in the development of OA. Therefore, the present study aimed to investigate the underlying influences of exogenous VEGF on articular cartilage degeneration in OA model rat. A total of 24 male Sprague-Dawley rats were randomly allocated into 3 groups. In the normal saline (NS) and VEGF groups, animals received bilateral anterior cruciate ligament (ACL) transection to establish the OA model; at 4 weeks post-surgery, the rats received local intra-articular injections of 100 mu l NS or VEGF solution, respectively, every week for 4 weeks. The Control group received neither surgery nor injections. All animals were sacrificed at 12 weeks following surgery. Prominent cartilage degeneration was observed in rats in the NS- and VEGF-injected groups. The extent and the grade of cartilage damage in the VEGF-injected group were notably more severe compared with those in the NS-treated group. Western blotting results demonstrated that the expression levels of aggrecan and type II collagen were significantly reduced in OA model rats that were treated with VEGF. In addition, the expression levels of matrix metalloproteinase (MMP)-3, MMP-9, MMP-13, a disintegrin and metalloproteinase with thrombospondin motifs (a disintegrin and metalloproteinase; ADAMTS)-4, -5 and -12, type III collagen and transforming growth factor-1 were significantly increased following VEGF administration. Results from the present study indicated that VEGF may exhibit a promoting role in the development of OA by destroying articular cartilage matrix.