Science & Healthcare

Introduction: When nuclear testing and nuclear bombing in the lower atmosphere as a result of neutron activation of chemical elements in the soil and other materials produced beta and gamma emitting radionuclides. Manganese 56 (T1 / 2 = 2.58 hours) - is one of the dominant beta- and gamma-emitters within few hours after the neutron irradiation of soil dust following nuclear explosion in atmosphere. The effects of exposure to residual radioactivity from nuclear explosions are the subject of discussions and research of the consequences of nuclear tests and the atomic bombing.

Aim: to investigate the quantitative and qualitative composition of large intestinal microflora of internal and external exposure of rats.

Materials and methods: to achieve this aim an experiment was conducted on 39 white laboratory «Wistars» rats. MnO₂ powder was activated by a neutron beam to obtain radioactive ⁵⁶Mn. Rats were divided into four groups: ⁵⁶MnO₂, non radioactive MnO₂, ⁶⁰Co- γ ray (2 Gy, whole body), and control. 56MnO2 was obtained by neutron activation of 100 mg of MnO2 powder using a Baikal-1 nuclear reactor (Kurchatov, Kazakhstan) and then sprayed into a sealed box containing the rats. Whole-body γ-ray irradiation of 2 Gy was performed at a dose rate of 2.6 Gy/min using a Teragam K-2 unit (UJP Praha, Praha-Zbraslav. Czech Republic). On days 3, 14, and 60 after exposure, the microbiological examination of faeces samples were taken, in which the content of the main representatives of the intestinal flora: Bifidobacterium, Lactobacillus, Escherichia, opportunistic enterobacteria. The results were analyzed using non-parametric Mann-Whitney statistics (SPSS 20 program) [6]. Statistically significant differences were considered between the control and experimental groups at p <0.05.

Results: The study shows the pronounced effect of irradiated ⁵⁶MnO₂ in comparison with the external ⁶⁰Co irradiation on the composition of the microflora of the large intestine. On the third day after irradiation with 56MnO2, the number of the main representatives of the microflora of the large intestine of bifido- and lactobacilli decreased, and the number of conditionally pathogenic bacteria increased. These changes were resistant up to 60 days. External gamma irradiation from ⁶⁰Co in a dose of 2 Gy also changes the intestinal microflora, although the above changes were unstable and gradually returned to the control level.

Conclusion: Internal and external irradiation leads to the development of dysbiosis, characterized by quantitative and qualitative changes in the intestinal microflora.