Correlation between osteopontin and caveolin-1 in the pathogenesis and progression of osteoarthritis.

Previous studies have produced contradictory results with regard to the role of osteopontin (OPN) and caveolin-1 in the pathology of osteoarthritis (OA). Thus, the aim of the present study was to investigate the correlation between OPN and caveolin-1 in the pathogenesis and progression of OA. Cartilage tissue samples were obtained from 50 individuals, of which 40 had been diagnosed with OA and 10 were normal healthy individuals. The samples were ascribed to four groups, namely the normal, minor, moderate and severe groups, on the basis of the improved Mankin grading system. Immunohistochemistry was applied to analyse the expression of OPN and caveolin-1. OPN and caveolin-1 were detected in the tissues of all four groups. The mutual comparisons of OPN expression levels among the groups revealed statistically significant differences (P<0.05). In addition, the mutual comparisons of caveolin-1 expression levels among the four groups demonstrated statistically significant differences (P<0.05), with the exception of that between the moderate and severe groups (P>0.05). Improved Mankin grading system scores were shown to correlate with the average grey level of OPN expression in each group (r=-0.824, P<0.01) and the average grey level of caveolin-1 expression (r=0.725, P<0.01). Furthermore, a statistically significant negative correlation was observed between the average grey levels of OPN and caveolin-1 expression (r=-0.676, P﹤0.05). Therefore, the results of the present study indicated that the correlation between OPN and caveolin-1 may play a significant role in the pathogenesis and progression of OA.