Genotoxicity assessment of cadmium chloride in Labeo rohita (Hamilton, 1822) based on induction of micronuclei and other nuclear abnormalities

The genotoxic potential of environmentally realistic concentrations of cadmium chloride (CdCl2) was assessed in vivo using micronucleus assay on gill epithelial cells, erythrocytes of peripheral blood and cephalic kidney of Labeo rohita. Fish were exposed to two different concentrations (0.37 and 0.62 mg l(-1)) of CdCl2 for 24, 48, 72 and 96 h. In addition to micronuclei (MN), other nuclear abnormalities (NA) such as induction of nuclear bud (NBu) and fragmented-apoptotic (FA) cells were also evaluated for assessment of cytotoxicity of CdCl2. MN and NA frequencies in all the observed tissues were high in fish exposed to both the concentrations as compared to control. The frequency of MN was highest in the gill cells followed by erythrocytes of peripheral blood and cephalic kidney in fish treated with both the toxicant concentrations. However, the higher concentration of CdCl2 caused significant (p<0.05) induction of MN after 48 h, while the lower concentration caused marked induction after 96 h of acute exposure. A concentration and time dependent elevation in MN and other NA frequency was noticed in all the three types of tissues tested. A three-fold increase in the occurrence of MN was observed in gill cells of the fish treated with CdCl2 at higher concentration as compared to that of lower concentration.