Assessing the genotoxic potentials of arsenic in tilapia (Oreochromis mossambicus) using alkaline comet assay and micronucleus test.

Chemosphere. 2011 Mar 5. [Epub ahead of print]
Ahmed MK, Habibullah-Al-Mamun M, Hossain MA, Arif M, Parvin E, Akter MS, Khan MS, Islam MM.
Department of Fisheries, University of Dhaka, Dhaka-1000, Bangladesh.
Abstract: This experiment was conducted to study the genotoxic potentials of sodium arsenite (NaAsO(2)) in freshwater fish Oreochromis mossambicus by using alkaline comet assay and micronucleus (MN) test. Fish were exposed to three different concentrations (3ppm, 28ppm and 56ppm) of arsenic and gill, liver and blood tissue samples were collected after 48h, 96h and 192h of exposure. Arsenic exposure induced DNA damage in all tissues examined in a concentration dependent manner. A significant (p<0.05) increase in the comet tail DNA (%) of the exposed fish liver, gill, and blood was observed after 48h and 96h of exposure, but a decline in DNA damage was recorded in all the tissues at all the three concentrations studied after 192h of exposure. Liver tissue exhibited significantly (p<0.05) higher DNA damage at all the concentrations examined, followed by gill and blood. Higher liver tail DNA (51.38±0.21%) refers that it is more prone to injury to arsenic toxicity than the gill and blood. In blood samples arsenic induced micronucleus formation in a concentration dependent manner and highest (5.8±0.46%) value was recorded in 56ppm after 96h of exposure, whereas, it was decreased after 192h of exposure at all the three concentrations of NaAsO(2) examined which refers to the DNA repairing ability of fish to arsenic toxicity. The results of this study depict the genotoxic potentials of arsenic to fish which in turns provide insight on advanced study in aquatic toxicology.