Aim: to study the effect incubation in NaCI hypertonic solutions on the yield of DNA single-strand breaks (SSB) and alkali-labile sites (ALS) induced by y-radiation and hydrogen peroxide in human peripheral blood lymphocytes in vitro. Material and methods. The lymphocytes isolated from the peripheral blood of healthy women donors aged 21-26 years were used for the study. Cell irradiation at doses of 1, 2, 3 and 5 Gy was performed using the "AGAT P1" unit (Russia, y-radiation source — 60Co, a dose rate of 1 Gy/min) at 4°C. In case of hydrogen peroxide exposure (25, 50 and 100 uM) the cells were incubated for 15 minutes at 4°C. Analysis of the DNA SSB and ALS was performed using the alkaline DNA comet assay. Results. Incubation of cells in 0.35 M NaCI solution (non-histone proteins dissociation) increases the yield of DNA SSB and ALS induced by v-radiation and hydrogen peroxide at ~ 1.3 times. Increasing the NaCI concentration to 0.6 M (linker histone H1 dissociation) leading to almost double increase in the DNA damage yield (~ 1.7-1.8 times). Further increasing the NaCI concentration leading to disruption of the structure of nucleosomes (1.2 M) and almost complete chromatin deproteinization (2 M) increased the yield of DNA damage not such pronounced as expected (~ 2.2-fold at 2 M concentration). Conclusion. The results showed that incubation in NaCI hypertonic solutions significantly increases the sensitivity of lymphocytes to DNA damaging action of free radicals.
Vorobyeva N.Yu., Arkhangelskaya E.Yu., Bushmanov A.Yu., Osipov A.N. Effect of incubation in sodium chloride hypertonic solutions on y-radiation and hydrogen peroxide induced DNA damage in human peripheral blood lymphocytes // Saratov Journal of Medical Scientific Research, Vol. 10, Issue 4, 2014, pp. 735-739

Aim: to compare the amount of DNA single-strand breaks (SSB) and alkali-labile sites (ALS) induced by DNA 365 nm ultraviolet (UV) versus X-rays radiation in human peripheral blood lymphocytes at in vitro conditions. Material and methods. Blood lymphocytes were isolated in a Ficoll-verografin density gradient. Irradiation of cells was performed using BLX-365 UV-unit (wavelength 365 ± 10nm)and RUSTM1 biological X-ray unit. Analysis of DNA SSB and ALS was carried out using comet assay at alkaline conditions. Results. For the first time it was demonstrated that the amount of SSB and ALS induced by 365 nm UV radiation at a dose of 10 kJ/m2 in human lymphocytes corresponds to the effect of X-rays at a dose of- 1 Gy. Conclusion. Exposure of human peripheral blood lymphocytes to 365 nm UV radiation at a dose of 1 kJ/m2 induces - 100 DNA SSB per cell.
Smetanina N.M., Pustovalova М.V., Bushmanov A.Yu., Osipov A.N. Comparative study of the amount of DNA single-strand breaks and alkali-labile sites in human peripheral blood lymphocytes exposed to 365 nm UV versus X-ray radiation // Saratov Journal of Medical Scientific Research, Vol. 9, Issue 4, 2013, pp. 791-795