The leukocyte blood composition and micronuclei in the erythrocytes of amphibians in the polluted reservoirs of Nizhni Novgorod region

Autecological researches are necessary to obtain populations characteristics providing steady existence of animals in the conditions of an anthropogenic stress; they have practical significance connected with the assessment of the environment quality by bioindication. The purpose of this work was the autecological investigation of leukocyte composition and the micronucleation in red blood cells of amphibians. The object of the research was marsh frogs (70 specimens) and pool ones (35 specimens) in the water bodies of Nizhni Novgorod region. The duration of the observation was two years. The main methods were qualitative and quantitative analysis of leukocytes and red blood cells, hydrochemical analysis by spectrophotometry. Statistical processing was carried out by the methods of nonparametric statistics, correlation method, dispersive analysis (R-studio, Statictica). The main pollutants of water bodies were defined and the specific combinatory index of water impurity was calculated. It was established that the number of leukocytes and erythrocytes in the blood of amphibians was decreased. Interspecies distinctions were revealed in the content of myelocytes, basophiles, eosinophils and lymphocytes. The parameters of leukocytal blood system of pool frogs in specific conditions of their habitat were mostly caused by the dynamics of lymphocytes. WBCs of marsh frogs were characterized by the increase in the share of immature forms of neutrophilic granulocytes and the change of the ratio between the share of big and small lymphocytes. Indicators of blood correlated with the content of iron (r = 0.85, р = 0.029) and chlorides (r = -0.87, р = 0.021) in a reservoir. It was found that at higher levels of water pollution for two years, the shares of the erythrocytes containing the micronuclei of attached and disintegrated types increased. It occurred on the background of the decrease in the share of rounded micronuclei. For the first time the size of micronuclei of different types occurring in erythrocytes of amphibians was measured. It was shown that the area of the disintegrated micronuclei surpassed that of rounded and attached micronuclei. The results revealed the features of leukocytal blood composition and cytogenetic homeostasis in the populations of marsh and pool frogs in the specific biotopical conditions.