Fig. 5. Effects of prunetin on IL-1β-induced secretion of MMP-3 and caseinolytic activity of MMP-3 in rabbit articular chondrocytes.

Primary cultured rabbit articular chondrocytes were pretreated with varying concentrations (1, 10, 50, and 100 µM) of prunetin for 2 h and then stimulated with IL-1β (10 ng/mL) for 24 h. Culture supernatants were collected for measurement of both the levels of produced and secreted MMP-3 by western blot analysis and the proteolytic activity of MMP-3 by casein zymography. Three independent experiments were performed and the representative data were shown. The signal intensity of each band was analyzed by GelQuant software (DNR Bio-Imaging Systems Ltd., Jerusalem, Israel). Each bar represents a mean±S. E.M. of three independent experiments in comparison with that of the control set at 100%. ^*significantly different from control (p<0.05), ⁺significantly different from IL-1β alone (p<0.05) (cont: control, concentration unit is µM).