[STUDY OF TOTAL ANTIOOCIDANT STATUS OF THE ORGANISM AS A POSSIBLE BIOMARKER OF DOSE AND EFFECT OF RADIATION EXPOSURE]

In presented article, by means of a comparative analysis of the relationship between the dose-dependent alterations in the organism's redox status, measured by the innovative method developed by us and the standard methods used for assessing catalase and superoxide dismutase activity, and an end radiobiological effect, was attempted the preliminary assessment of the possibility to apply the parameter of blood plasma total antioxidant activity (TAA) as marker of dose and effect of radiation exposure. The experiments were carried out on white mice randomly divided into groups of irradiated and sham irradiated animals. The mice were exposed to a whole body gamma irradiation by source Cesium-137 (137Cs) at doses of 5 and 7 Gr, a dose rate of 1.1 Gr / min. After 5 days of beginning of observation in animals' blood measurements of the activity of antioxidant enzymes (superoxide dismutase - SOD and catalase - CAT) and total antioxidant activity by spectrophotometric method were evaluated. Parallel monitoring of animal survival was conducted. At the given stage of the study, applicability of OAA as a marker of dose-dependent alterations in antioxidant status was assessed by the criteria of sensitivity and linearity, and as a marker of the effect the strength of the relation between the antioxidant status indicators and the final radiobiological effect, measured by animal life span in post- radiation period (time-effect) For comparative analysis of the effects of radiation on the levels of antioxidant status indicators (SOD, catalase, OAA), ANOVA methods were used, the nature of the causal relationship between levels of antioxidant status and the life span of laboratory animals was analyzed on the basis of the Cox proportional intensity model with time covariates, preliminary processing of data, basic calculations and visualization of the results were carried out using a mathematical package that " STATISTIC 12". The received results testify to the significantly high sensitivity of the total redox-status indicator (OAA) to the dose of irradiation, which makes it possible with full justification to consider it as a promising candidate of the biological exposure dose marker. In addition, the indicator of the total antioxidant status (OAA) of the body allows predicting the dose dependence of the survival of laboratory mice more accurately than the indices of the activity of individual antioxidant enzymes (catalase and SOD), which makes it possible to consider it as a promising candidate for the biomarker of the dose and the effect of radiation exposure.