Fig. 1.

Metformin protects RPE cells against MGO-induced cytotoxicity.

(A) ARPE-19 cells were stimulated with MGO (300 μg/ml) for indicated time points. Cell viability was determined by Annexin V-FITC/PI staining using FACScalibur. (B) Cells were pretreated with metformin (2, 6 and 20 mM) 30 min prior to MGO (300 μg/ml) treatment for 6 h. Cell viability was determined by Annexin V-FITC/PI staining. (C) Metformin (6 or 20 mM) was administered at 30 min pre-treatment before MGO, co-treatment with MGO, or post-treatment at 0.5, 1, 2, or 4 h after MGO (300 μg/ml). After 6 h of MGO treatment, cell viability was determined by Annexin V-FITC/PI staining. Data were the mean ± S.E.M. from at least 3 independent experiments. *p < 0.05, indicating the significant effect of MGO; #p < 0.05, indicating the blockade effect of metformin. (D) Cells were pretreated with 6 mM metformin for 30 min followed by MGO (300 μg/ml) treatment for 3 or 6 h. Cell lysates were prepared for immunoblotting. Data were representative of 3 independent experiments.