Oxidative Stress and Calcium Dyshomeostasis Mediated CPF-Induces EPC Cell Apoptosis and Necroptosis

Chlorpyrifos (CPF) is a broadly used organophosphate insecticide, and as environmental contamination has been confirmed to be harmful to the health of humans and animals, the effects of CPF on fish are still unclear. We aim to detect whether CPF has effects on the common carps, and identify the mechanisms of the effects. In accordance with the IC50 of CPF for epithelioma papulosum cyprini (EPC) cells was 8.945 µM, 0, 3, 5 and 7 µM CPF were marked as C, L, M and H group. The results indicated that CPF exposure led to oxidative stress in EPC cells. Moreover, Calcium ion (Ca2+) imaging indicated that CPF triggers Ca2+ dyshomeostasis, as induced ER Ca2+ fluxed into cytoplasm and mitochondrial, and mediates endoplasmic reticulum (ER) stress and mitochondrial Ca2+ overload, which have further confirmed with the increased transcription of ER stress related genes. Meanwhile, CPF induced collapse of mitochondrial membrane potential (MMP), enhancement of ROS generation and depletion of ATP level in both cytoplasm and mitochondrial, substantiated mitochondrial dysfunction has been evoked. Besides, the AO/EB staining and flow cytometry analysis ascertained that CPF induces apoptosis and necroptosis in EPC cells. Hence, we further verified that via determining the expression of apoptotic pathway genes and necroptotic pathway genes. Consequently, we illuminated the mechanisms of CPF effects on the common carps from the perspective of Ca2+ homeostasis, and provided a novel concept for investigating the toxicity of CPF as environmental pollution on aquatic organisms.