Figure 1. Hyperosmolar stress induced dose-dependent increase in MCP-1 mRNA in ARPE-19 cells. ARPE-19 cells were incubated for 8 h with iso-osmolar medium (Iso) or media containing additional increasing concentrations of NaCl (Na25, Na50, Na100; A) or sucrose (Su50, Su100, Su200; B) prior to MCP-1 mRNA levels determination by RT-qPCR, as described under Methods. Data are expressed as the mean ± SEM (n = 4) of MCP-1 mRNA levels (in fold expression) over the Iso set to 1, following normalization with appropriate reference genes (HPRT1, B2M, ATP5B). Data were analyzed using the conformity t test and the paired t test. **p < 0.01 indicates statistical significance compared to Iso; $$p < 0.01 indicates statistical significance compared to Na25 or Su50; ##p < 0.01 indicates statistical significance compared to Na50 or Su100.