Study the impact of astaxanthin on developing of genomic instability in human peripheral blood lymphocytes irradiated in vitro on G2 phase of cell cycle

Abstract

Objective. To identify the possibility of modification by astaxanthin the level of genome damages induced by gamma quanta in the culture of human peripheral blood lymphocytes exposed in vitro on postsynthetic (G2) phase of the first mitotic cycle. Materials and methods. Peripheral blood lymphocytes from four apparently healthy volunteers 35-51 years old were cultivated using modified micromethod. To obtain genomic damages in G2 phase of the first mitotic cycle the part of cultures was irradiated by γ-quanta in dose 1.0 Gy through 46 hours of cultivation. Astaxanthin in final concentration 20 µg/ml was exposed to lymphocytes’ cultures before the irradiation. Cytogenetic analysis the uniformly stained slides of metaphase chromosomes was carried out to determine the frequencies of chromosome and chromatid types of aberrations. Using the method of individual cells electrophoresis (Comet assay) the relative level of DNA damages (Tail Moment index) and the frequency of apoptotic cells with high level of DNA fragmentation were evaluated. Results. Mean-group frequencies of chromosome aberrations after gamma irradiation of lymphocytes in vitro exceeded those without radiation exposure and were 72.35 ± 1.17 and 2.46 ± 0.30 per 100 metaphases, respectively (p < 0.001), mainly due to chromatid type of aberrations (58.32 ± 1.29 per 100 metaphases). Adding of astaxanthin into culture medium before the irradiation did not result in changes as in the frequency of chromosomal damages (71.54 ± 1.34 per 100 metaphases) as in the spectrum of aberrations - also prevailed chromatid type of aberrations (58.47 ± 1.47 per 100 metaphases). The increase of Tail Moment index after radiation exposure (from 3.84 ± 0.36 to 12.06 ± 1.88, respectively, p < 0.001) and lack of significant impact of astaxanthin on this index in the irradiated lymphocytes (8.96 ± 2.39, p > 0.05) was established, ie astaxanthin didn’t change the relative level of radiation-induced DNA damages. Also apoptogenic effect of astaxanthin was not found: frequency of apoptotic cells were (2.25 ± 1.49) % in cultures of intact lymphocytes, (2.08 ± 1.54) % in irradiated cultures and (1.78 ± 1.25) % under joint action of gamma radiation and astaxanthin (p > 0.05). Conclusions. No impact of astaxanthin on genomic instability induced by gamma irradiation in vitro in cultures of human peripheral blood lymphocytes on postsynthetic (G2) phase of first mitotic cycle had been established.