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.

Catla catla的肾脏, 长期暴露于亚致死浓度 (0.24 μg/L 和 0.41 μg/L) 的氯氰菊酯显示抗氧化剂超氧化物歧化酶 (SOD)、过氧化氢酶 (CAT)、谷胱甘肽-S-转移酶 (GST) 和15 天后谷胱甘肽 (GSH) 减少，随后最多下降 45 天。脂质过氧化 (LPO) 在整个暴露期间保持升高。组织学表现为增殖的造血组织、肾小管和肾小球变性。在治疗的第 45 天观察到平均组织变化程度 (DTC) 的最大增加。超微结构研究描述了细胞质空泡化、碎片化 RER、溶酶体增殖、线粒体变性和肾小管上皮内层的退行性变化。各种生物标志物的主成分分析 (PCA) 产生了两个成分 PCI（SOD、GST、GSH、LPO 和 DTC）和 PCII (CAT)。这些发现表明，长期接触氯氰菊酯会导致鱼肾发生各种病理改变，进而可能干扰正常的肾脏排泄机制。