Accumulation, histopathological effects and response of biochemical markers in the spleens and head kidneys of common carp exposed to atrazine and chlorpyrifos

This study assessed the impacts of atrazine (ATR), chlorpyrifos (CPF) and combined ATR/CPF exposure on the immune organs of common carp (Cyprinus carpio L.). The carp were sampled after a 40-d exposure to CPF and ATR, individually or in combination, followed by a 20-d recovery to measure the acid phosphatase (ACP), alkaline phosphatase (ALP), Na+/K+-ATPase, superoxide dismutase (SOD) and malondialdehyde (MDA) content. In addition, we also investigated histopathological changes and pesticide residues in the spleen and head kidney. The results revealed that the responses of SOD, MDA, ALP, ACP, and Na+/K+-ATPase to ATR, CPF and ATR/CPF combination exposure presented in a dose-dependent manner. The ACP activity and MDA content were significantly induced with increasing concentrations of ATR, CPF and combined ATR/CPF. However, the enzyme activities (SOD, ALP, and Na+/K+-ATPase) were reduced under exposure to increasing concentrations of these compounds. The accumulated amounts of ATR, CPF, and their metabolites in the spleens and head kidneys tissues exhibited dose-dependency. Pathological changes included tissue damage that was more severe with increasing exposure doses. SOD activity negatively correlated with MDA accumulation. The biochemical parameters exhibited sensitivity to ATR and CPF, suggesting that they may act as potential biomarkers for assessing the environmental ATR and CPF risk for carp.