Figure 2. Suppression of TNF-α-induced IL-6 and Ccl2 mRNA by OTC in polarized, fully differentiated ARPE-19 cells. ARPE-19 cells were cultured to a state of confluency and then maintained in culture for an additional for 6 weeks to facilitate their polarization and differentiation. The cells were then exposed to tumor necrosis factor-α (TNF-α; 10 ng/ml; 24 h incubation) in the presence or absence of L-2-oxothiazolidine-4-carboxylic acid (OTC; 0.5 mM) and nicotinic acid (NA; 1 mM; positive control). Quantitative polymerase chain reaction (qPCR) analysis of (A) interleukin-6 (IL-6) and (B) chemokine (C-C) motif ligand 2 (Ccl2) mRNA expression. *p<0.01 compared to untreated, control; **p<0.01 compared to TNF-α-treated cells.