Impact of cypermethrin in nephrocytes of freshwater fish Catla catla

The kidney of Catla catla, chronically exposed to sub-lethal concentrations (0.24 μg/L and 0.41 μg/L) of cypermethrin revealed a significant elevation in the activity of antioxidants superoxide dismutase (SOD), catalase (CAT), glutathione-s-transferase (GST) and reduced glutathione (GSH) after 15 days, followed by a decline of up to 45 days. Lipid peroxidation (LPO) remained elevated throughout the exposure duration. Histology presented proliferated haematopoietic tissue, tubular and glomerular degeneration. The maximum increase in the mean degree of tissue change (DTC) was observed on the 45th day of treatment. Ultra-structure study depicted cytoplasmic vacuolation, fragmented RER, the proliferation of lysosomes, mitochondrial degeneration, and degenerative changes in the epithelial lining of renal tubules. Principal component analysis (PCA) of various biomarkers generated two components PCI (SOD, GST, GSH, LPO and DTC) and PCII (CAT). These findings suggest that long term exposure to cypermethrin can lead to various pathological alterations in the fish kidney which in turn might interfere with normal renal excretory mechanism.