Evaluation of Genotoxicity induced by Cobalt to Freshwater Fish, Cirrhina mrigala using Micronuclei Assay

Abstract

Due to industrial advancement, a variety of toxic chemicals including metals are released into the aquatic environment which not only disturbs the physico-chemical properties of the water bodies but also influences the aquatic food chain to cause physiological and cytogenetic alternations in the aquatic animals. Metals have the ability to produce reactive oxygen species (ROS) that would cause the oxidative of nucleic acid. Micronucleus test has been commonly used for the estimation of biological impacts of water pollutants on genotoxic damage in fish. Therefore, the present research work was designed to check the genotoxic potential of cobalt for fish Cirrhinus mrigala by using a micronuclei assay. Fish were exposed to the various sub-lethal concentrations of cobalt metal such as 2/3rd, 1/3rd, 1/4th, and 1/5th of LC50 concentration for one month and sampling was done after 10 days intervals. Blood sample from the caudal vein of fish was collected to see the micronuclei and binucleated nuclei. Results showed that all test concentrations induced micronuclei and binucleated nuclei in peripheral erythrocytes of C. mrigala. Maximum nuclear abnormalities in peripheral erythrocytes of C. mrigala were observed in 2/3rd concentration followed by the orders: 1/3rd 1/4th 1/5th.Due to industrial advancement, a variety of toxic chemicals including metals are released into the aquatic environment which not only disturbs the physico-chemical properties of the water bodies but also influences the aquatic food chain to cause physiological and cytogenetic alternations in the aquatic animals. Metals have the ability to produce reactive oxygen species (ROS) that would cause the oxidative of nucleic acid. Micronucleus test has been commonly used for the estimation of biological impacts of water pollutants on genotoxic damage in fish. Therefore, the present research work was designed to check the genotoxic potential of cobalt for fish Cirrhinus mrigala by using a micronuclei assay. Fish were exposed to the various sub-lethal concentrations of cobalt metal such as 2/3rd, 1/3rd, 1/4th, and 1/5th of LC50 concentration for one month and sampling was done after 10 days intervals. Blood sample from the caudal vein of fish was collected to see the micronuclei and binucleated nuclei. Results showed that all test concentrations induced micronuclei and binucleated nuclei in peripheral erythrocytes of C. mrigala. Maximum nuclear abnormalities in peripheral erythrocytes of C. mrigala were observed in 2/3rd concentration followed by the orders: 1/3rd 1/4th 1/5th.