FIGURE 2.

Antioxidant attenuated the CSE-induced ER stress and protected RPE cells from apoptosis. ARPE-19 cells were pretreated with 1 mm of NAC for 6 h and then incubated with 320 μg/ml of CSE for 6–24 h. A, representative Western blots of p-eIF2α and eIF2α in cells treated with CSE for 6 h, ATF4 and CHOP (CSE-treated for 12 h), and cleaved-caspase-3 (CSE-treated for 24 h). B, densitometry analysis of p-eIF2α (normalized with eIF2α), ATF4, CHOP, and cleaved-caspase-3 (normalized with β-actin). C, Nrf2 levels were examined by Western blotting. D, apoptosis was examined by TUNEL assay after CSE treatment for 24 h. Scale Bar: 50 μm. E, quantification of TUNEL-positive cells. F, cell viability result of ARPE-19 cells after CSE 24 h treatment with or without NAC pretreatment. G, cell death was detected using in situ Trypan Blue staining after CSE treatment for 24 h. All data were expressed as mean ± S.D., from three independent experiments. *, p < 0.05; **, p < 0.01 versus control; †, p < 0.05; ‡, p < 0.01 vs. CSE.