Uranium (238U)-induced ROS and cell cycle perturbations, antioxidant responses and erythrocyte nuclear abnormalities in the freshwater iridescent shark fish Pangasius sutchi

The accumulation of uranium was, in order of magnitude, measured as gills > liver > brain > tissue, with the highest accumulation in the gills. It was observed that exposure to 238U significantly reduced antioxidant enzymes such as superoxide dismutase, catalase, and lipid peroxidase. The analysis of DNA fragmentation by comet assay and cell viability by flow cytometry was performed at different time intervals. DNA histograms by flow cytometry analysis revealed an increase in the G2/M phase and the S phase. The long-term 238U exposure studies in fish showed increasing micronucleus frequencies in erythrocytes with greater exposure time. The higher the concentration of 238U is, the greater is the effect observed, suggesting a close relationship between accumulation and toxicity. A possible ROS-mediated 238U toxicity mechanism and antioxidant responses have been proposed.