Analyses of impact of metal ion contamination on carp (Cyprinus carpio L.) gill cell suspensions

The decline in fish population because of water contamination is problem. As a result of direct exposure in water, it has been readily accepted that the gills are the main site of water contamination and toxicity (e.g., metal ions). In the present study, we investigated metal ion contamination on the functional capacity of carp gill cells with antioxidant interactions in an in vitro study. The extent of cellular membrane damage, lipid peroxidation (LPO) (as TBARS levels), and glutathione (GSH) content were investigated after the addition of two metal ion compounds (viz., CuSO4 and HgCl2) in various concentrations (300, 500, 700, 1000, and 3000 W) to gill cell preparation of the freshwater fish carp (Cyprinus carpio L.) with modulations by bovine serum albumin (BSA) (0.5% and 1.0%) and dimethyl sulfoxide (DMSO) (0.5%) as free-radical scavengers. The Comet assay technique was also performed for the highest concentrations of the two mentioned metal ions as an index of DNA breaks. The outcomes were as follows: (1) Copper and mercury increased the rate of LPO dose dependently (r = +0.995 and r = +0.993, respectively; p < 0.001), but the GSH content was only marginally affected (r = -0.787 and r = -0.844, respectively; p < 0.05). (2) Depletion of GSH molecules by copper had a wider range than mercury. (3) In the highest concentration of metal ions (3000 muM), both DMSO and 1.0% BSA showed a pro-oxidative potential to elevate the levels of TBARS (p < 0.001), but for other concentrations when supplemented with three scavengers, a fall in the levels of the latter was found. (4) The addition of 1.0% BSA to medium containing 3000 muM of metal ions caused a significant decline in GSH content (p < 0.01). (5) Copper and mercury could cause a high rate of DNA breaks (single stranded) in carp gill cell suspensions as a Comet appearance. These findings indicate that copper and mercury have a deleterious influence on membrane integrity and GSH content in a relatively dose-dependent manner. The complexes of metal ions and thiol (-SH) residues of cell proteins could also act as a potential cell toxicant leading to disturbances in cell functions causing cell death. DNA fragmentation is frequent in metal ion contamination.