Hepatic effects of low-dose rate radiation in natural mouse populations (<i>Apodemus uralensis</i> and <i>Apodemus agrarius</i>): comparative interspecific analysis

<b>Hypothesis:</b> Natural mouse populations in radioactive contamination zone provide adequate information about dose loads and biological effects for ‘non-human biota’. The comparative analysis of the responses of different species of mice allows us to reveal the possible variation in the effects of low-dose rate radiation relative to the ecological-physiological and functional-metabolic features of the species. <b>Materials and methods:</b> Objects of study – two sympatric rodent species [pygmy wood mouse (<i>Apodemus uralensis</i> Pallas, 1811) and striped field mouse (<i>Apodemus agrarius</i> Pallas, 1771)] caught on the territory of the East-Ural radioactive trace (EURT). The EURT zone is consequence the Kyshtym accident in South Urals in 1957. Nowadays, the main dose-forming radionuclide is β-emitting ⁹⁰Sr. The individual dose rate of impacted mice caused by internal exposure to ⁹⁰Sr varied from 0.021 to 0.152 mGy/day. The baseline functional-metabolic characteristics of the liver were researched: protein-, lipid-, and glycogen-synthesizing processes; glycolysis; aerobic synthesis of ATP; lipid peroxidation; and the H₂O₂-scavenging enzymatic status; and the functional activity of the genome. <b>Results:</b> The hepatic shifts for impacted populations are amplified with increasing dose rate of irradiation, regardless of which species is considered. But, the response of closely related species of rodents to irradiation is different both in the vector and the level (in <i>A. agrarius</i> sample was 2 time higher than that for <i>A. uralensis</i>). <b>Conclusion:</b> The radiation-induced hepatic shifts in <i>A. uralensis</i> from the EURT area correspond to the chronic response under stressful environmental conditions. The impacted population of <i>A. agrarius</i> can be considered the more reactive species to the radiation burden, demonstrating an acute effect. The interspecies contrast in the radiation response is associated with the original interspecies differences (background rodents’ samples in 28 km from the impact study site), and also the degree of residency of the species in the impact plots.