In vitro tests of resveratrol radiomodifying effect on rhabdomyosarcoma cells by comet assay

Cancer is a global public health problem. Resveratrol is a defensive polyphenol that is synthesized by a wide variety of plants in response to exposure to ultraviolet radiation or also due to mechanical stress caused by the action of pathogens and chemical and physical agents. Grape vines have a high capacity to produce resveratrol, so grape juice and wine, mainly red wine, are considered good sources of resveratrol. The protective effects of resveratrol include promotion of antiinflammatory response, antitumor activity and prevention of degenerative diseases, reduced incidence of cardiovascular diseases and inhibition of platelet aggregation, among others. Therefore, resveratrol is considered to be a cell protector. However, at high concentrations, resveratrol promotes contrary effects by sensitizing cells. The aim of this study was to investigate in vitro the radiomodifying effect of resveratrol in culture of human rhabdomyosarcoma cells (RD) by applying the comet assay to evaluate the cell damage and repair capacity. The LD₅₀ (lethal dose) obtained was 499.95 ± 9.83 Gy (Mean ± SD) and the CI₅₀ (cytotoxicity index) was 150 μM in the RD cells. Based on these data, it was defined the gamma radiation doses (50 and 100 Gy) and resveratrol concentrations (15, 30 and 60 μM) to be used in this study. The results indicated that resveratrol acts as a cell protector at a concentration of 15 μM and has a cytotoxic effect at 60 μM. However, with the interaction of the gamma radiation, the concentration of 60 μM did not produce a statistically significant radiosensitizing effect.