Enhanced expression of caveolin-1 in articular chondrocytes in osteoarthritis

Abstract

To study the expression level of caveolin-1 in articular chondrocytes in patients with osteoarthritis (OA), and whether catabolic factor IL-1beta stimulate caveolin-1 expression in articular chondrocytes. In human OA cartilage, caveolin-1 mRNA was investigated by quantitative real-time RT-PCR while caveolin-1 protein was detected by immunohistologic analysis in 8 cases. OA model was prepared by unilateral anterior cruciate ligament and medial collateral ligament transection in 20 rats. In cultured OA chondrocytes, caveolin-1 mRNA expression was studied by RT-PCR and quantitative real-time RT-PCR, and caveolin-1 protein was analyzed by Western blotting. In 6 of 8 OA cases, human OA articular cartilage, higher expression levels of both caveolin-1 mRNA and caveolin-1 protein were found in advanced degenerated cartilage than less degenerated cartilage of the same joints. In rat OA model, upregulated caveolin-1 expression was found, which was associated with the degree of cartilage destruction. IL-1beta (10 ng/ml) upregulated caveolin-1 mRNA/protein expression in cultured OA chondrocytes for at least 48 hours. Enhanced expression level of caveolin-1 is associated with cartilage degeneration in OA. IL-1beta stimulates caveolin-1 expression in articular chondrocytes, which may be responsible for OA development.