Interspecies differences in oxidative stress response and radiocesium concentrations in rodents inhabiting areas highly contaminated by the chornobyl nuclear disaster

Abstract

Indicators of oxidative stress response were compared to radionuclide concentrations in rodents from highly contaminated sites around the Chornobyl Nuclear Power Plant, Ukraine, and uncontaminated reference areas. Three rodent species-Apodemus agrarius, Apodemus sylvaticus, and Clethrionomys glareolus (n = 121)-were collected from contaminated sites within the 10-km exclusion zone surrounding the Chornobyl Nuclear Power Plant and from uncontaminated reference areas in northern Ukraine. Liver samples were analyzed for superoxide dismutase (SOD) and catalase (CAT) activities, and muscle samples were analyzed for radiocesium activity. Superoxide dismutase and catalase activities differed significantly between reference and contaminated groups only for A. agrarius, and activities were lower in contaminated animals relative to those from reference sites. The SOD activity did not differ among species collected in reference areas. Among contaminated groups, A. agrarius had a significantly lower SOD activity than the other two species. Among reference groups, CAT activity for C. glareolus was significantly lower than for the other two species. Very high muscle radiocesium activities (up to 60,000 Bq/g) were found in rodents from contaminated areas, while the references for each species were at or below background. Clethrionomys glareolus had significantly higher muscle radiocesium concentrations than the other species collected at contaminated sites. There were no significant correlations between either SOD or CAT activities and muscle radiocesium concentrations for contaminated or reference animals in any species. There are significant interspecies differences in oxidative enzyme activities in rodents with lifetime exposure at highly radioactive contaminated sites. However, internal radiocesium concentration is not a sensitive predictor of these oxidative stress responses in individuals.