Paraquat Dichloride Induced Cytotoxicity in Primary Hepatocytes via an Antioxidative and Mitochondrial-Dependent Pathway.

The liver serves as the primary detoxification organ, playing a crucial role in protecting against environmental toxicants. Paraquat (PQ), a widely used herbicide in agricultural and domestic applications, has been extensively documented to induce severe toxicity in various tissues and disrupt multiple cellular signaling pathways. This study investigates the cytotoxic and genotoxic effects of PQ on isolated primary rat hepatocytes, obtained via the collagenase perfusion method. A comprehensive toxicity assessment was conducted, including cell viability at different PQ concentrations, reactive oxygen species (ROS) generation, reduced (GSH) and oxidized glutathione (GSSG) levels, mitochondrial membrane potential (MMP) collapse, lysosomal integrity, and lipid peroxidation (MDA) content. A significant increase in alanine aminotransferase (ALT) and aspartate aminotransferase (AST) leakage indicated hepatocellular membrane disruption. PQ exposure resulted in excessive ROS generation, mitochondrial dysfunction, oxidative stress, and apoptosis activation through the caspase-9/-3 signaling cascade. Notably, coincubation with the ROS scavenger N-acetylcysteine (NAC) significantly attenuated ROS generation, apoptosis, and hepatocyte damage, underscoring the role of oxidative stress in PQ-induced hepatotoxicity. These findings provide mechanistic insights into PQ-induced cytotoxicity, demonstrating that ROS overproduction and mitochondrial impairment are the primary drivers of hepatocyte injury. Given the extensive use of PQ and its potential environmental and human health risks, these findings are critical for understanding its toxicological impact and exploring antioxidant-based therapeutic strategies to mitigate liver damage.