GENISTEIN ALLEVIATES HIGH GLUCOSE INDUCED TOXICITY AND ANGIOGENESIS IN CULTURED HUMAN RPE CELLS

Objective: Genistein, an iso flavonoid has been shown to possess many biological activities including anti-inflammatory, antioxidant and anti-angiogenic property. It has been shown to be protective in dampening diabetes induced retinal inflammation in vivo . Therefore, the purpose of the present study is to investigate the effect of genistein on glucose induced toxicity in cultured human RPE cells (ARPE-19). Methods: ARPE-19 cells were challenged with normal glucose (NG 5 mM) and high glucose (HG1 25 mM & HG2 50 mM) concentrations with or without genistein (20 µM) for 24 h. The mRNA expression of aldose reductase (ALR) and VEGF was measured by real-time PCR using SYBR green. Inhibitory effects upon ALR activity were performed. The VEGF levels of cell supernatant were estimated by sandwich ELISA. Cellular viability and mitochondrial function upon genistein treatment were assessed using dye exclusion method and MTT assay respectively. Results : Genistein at the studied concentration showed 93% of cell viability and no marked toxicity was observed on cell growth. ARPE-19 cells challenged with HG1 and HG2 showed (2.32) and (2.48) fold increase in ALR expression as compared to NG. Significant increase in VEGF 165 expression was observed in ARPE-19 cells with HG1 and HG2 as compared to NG. The genistein treated cells significantly reduced the mRNA expression of both ALR and VEGF 165 . No significant increase in VEGF level was observed in ARPE-19 cell supernatant with HG1 and HG2 (220.68±5.24 and 228.96±7.19 pg/ml) as compared to NG (220.30±2.04 pg/ml), however, significant reduction was observed in response to treatment with genistein in HG1 and HG2 (155.51±9.33 and 122.85±4.76 pg/ml). Also ALR activity significantly reduced in genistein treated cells when compared with HG1 and HG2 concentrations. Conclusion: The results of the present study clearly demonstrate that genistein protects RPE cells from glucose toxicity. Genistein could be a prospective potent agent for treating complications linked with diabetes mellitus, such as diabetic retinopathy.