Fig. 3.
Effect of sRAGE or RAGE-knockdown on the AGE-BSA or S100A4 protein-induced expression of IL-6 and IL-8 in primary human OA chondrocytes. Primary OA chondrocytes were pre-treated with sRAGE (200 µg/ml) for 2 h and then stimulated with AGE-BSA (50 µg/ml) or S100A4 protein (25 ng/ml) or IL-1β (20 ng/ml) for 24 h. Human OA chondrocytes were transfected with RAGE-siRNA or control siRNA and then stimulated with AGE-BSA for 24 h. Expression of IL-6 (a) and IL-8 (b) mRNA was determined by real-time qPCR and normalized to GAPDH and compared with the levels present in untreated chondrocytes using a comparative ΔΔCT method. Production of IL-6 (c) and IL-8 (d) in the culture medium was quantified by IL-6- or IL-8-specific sandwich ELISA. Results are representative [mean (s.e.m)] of duplicate experiments with human OA chondrocytes obtained from two age- and sex-matched OA donors and differ without a common letter; P < 0.05.