Investigation of the effects of resveratrol and nicotinamide on cell proliferation and apoptosis in human retinal pigment epithelial cell line

Age-related macular degeneration (AMD) is a disease that is affected by metabolic, functional, genetic and environmental factors, oxidative stress-induced retinal pigment epithelium (RPE) damage is responsible in its pathogenesis, and there is no definitive treatment method, especially in the dry type. As a possible treatment option, it was aimed to demonstrate the potential efficacy of resveratrol and nicotinamide which are thought to have additive or synergistic effect by reducing mitochondrial dysfunction through their antioxidant, antiapoptotic and antiinflammatory properties in the dry type AMD model. In this study, healthy RPE cells were exposed to standard levels of oxidative stress to form the AMD model. The effect of the application of the active substances separately and in combination at the determined concentrations and times on cell proliferation of healthy and oxidative stress damaged RPE cells was measured by CCK-8 assay and apoptosis analysis of the same parameters was determined by flow cytometry method. In these analyzes, the effective doses that gave the best results for both active substances and the combined dose on SIRT1 gene expression level were determined by Quantitative Real-Time PCR method. Data were evaluated statistically. Among the active substances and combined dose options, the most effective cell viability (p<0.001) cell proliferation index (p<0.001) and cell apoptosis+necrosis values (p<0.001) in the direction of decreasing progression in the AMD model were determined to be occured in the combined dose application of 100µmol/L resveratrol+1mM/L nicotinamide at the 72nd hour incubation period. It was observed that the relevant combined dose did not show cytotoxic effect in the healthy RPE cell group (p>0.05) and provided a proliferative effect at a level that would provide wound repair (p=0.01) and it was also determined that it increased SIRT1 gene expression level in the damaged RPE cell group (p<0.001). In our study, it was observed that the combined dose application of the active substances effectively increased cell proliferation, cell viability and SIRT1 gene expression level and effectively decreased cell apoptosis+necrosis rate compared to their separate applications and it was determined that the two active ingredients showed a synergistic effect. Our project research is the first study to investigate the effect of the relevant combined dose in a dry type AMD model. Keywords: Resveratrol, Nicotinamide, Dry type age related macula degeneration