Mitogen-activated protein kinase phosphorylation in advanced glycation end product-BSA-stimulated osteoarthritis chondrocytes. (a) Effect of epigallocatechin-3-gallate (EGCG) on mitogen-activated protein kinase phosphorylation in advanced glycation end product (AGE)-BSA-stimulated osteoarthritis (OA) chondrocytes. After pretreatment with EGCG (25 to 150 μM) for 1 hour at 37°C, primary human chondrocytes (70 to 80% confluent) were incubated with AGE-BSA (400 μg/ml) for 45 minutes, and then the phosphorylation of p38, JNK, and ERK was determined by western blot analysis. (b) Band images were digitally captured and the band intensities (pixels/band) were obtained using the Un-Scan-It software and are expressed in arbitrary optical density units. Data shown are cumulative of two experiments. OD values presented as mean ± standard deviation; data without a common letter differ, P < 0.05.