Assessment of sublethal toxicity using proliferation markers in fish cell line-ICG exposed to agrochemicals

The purpose of this study was to determine the cytotoxic impact of four agrochemicals on Catla catla Hamilton 1822 Indian Catla catla gill cell line (ICG): insecticide [imidacloprid (IMI)], fungicide [curzate (CZ)], herbicide [pyrazosulfuron-ethyl (PE)], and fertilizer micronutrients (MN). The cytotoxic study was carried out by following the standard 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method for 96 hours and inhibition concentration (IC 50 ) values were determined. For further subacute studies, sublethal concentrations (1/20th of IC 50 as low dose, 1/10th of IC 50 as medium dose, and 1/5th of IC 50 as high dose) were selected. The ICG cells were exposed to all agrochemicals for 7 days and toxicity was analyzed with respect to untreated control. The morphological changes were observed and Trypan blue assay was used to understand the effect of agrochemicals on the ICG cells viability. The study reported a dose-dependent alteration in morphology and viability in ICG cells when exposed to agrochemicals. Furthermore, the expression of proliferative markers like proliferating cell nuclear antigen and cyclin genes (cyclin E and A) were analyzed through quantitative polymerase chain reaction. There was a significant decrease observed in gene expression of proliferating cell nuclear antigen, cyclin A, and cyclin E, which indicates the toxicity of agrochemicals IMI, CZ, PE, and MN, resulting in alterations in the cell cycle of the ICG cell line.