The impact of astaxanthin on the level of DNA methylation in irradiated in vitro human lymphocytes

Abstract

Objective. To investigate an effect of astaxanthin on global DNA methylation in human peripheral blood lympho-cytes exposed to γ-radiation in vitro. Methods. Samples of whole blood were diluted with RPMI-1640 medium in proportion 1: 10 and incubated at 37 °C for 3 h. Samples were exposed to γ-ray (emitter IBL-237C, dose-rate 2.34 Gy/min) in dose 1.0 Gy. Astaxanthin was added into culture medium in final concentrations 20.0 µg/ml before irradiation. The analysis of the global DNA methylation state was carried out using modified method of neutral single-cell gel electrophoresis (Comet assay) after digestion with the methylation-sensitive endonuclease HpaII. Results. For every experiment the analysis of the frequency distribution of «comets» was carried out. The treatment of non-irradiated and irradiated human peripheral blood lymphocytes with astaxanthin resulted to a statistically significant (p < 0.05) shift of comet distribution with tendency to increasing level of DNA migration which indicates increase in the pool of cells with a reduced level of DNA methylation. Conclusions. It has been found that astaxanthin in concentration of 20.0 µg/ml reduced the levels of global DNA methylation both in irradiated in vitro and native human lymphocytes. It suggests that astaxanthin has an effect on mechanisms of epigenetic regulation of gene expression.