Quinalphos induced intracellular ROS generation and apoptosis in human alveolar A549 cells

Abstract

The synthetic organophosphate insecticide, quinalphos is used widely due to its insecticidal and acaricidal properties. However, toxicity of quinalphos has not been well elucidated despite the increasing quinalphos ingestion cases worldwide. Our study emphasizes on the cytotoxic effect of quinalphos on human alveolar A549 cells. Quinalphos reduced cell viability, induced lactase dehydrogenase (LDH) release and intracellular reactive oxygen species (ROS) generation. DNA condensation and prominent apoptosis were detected in quinalphos-treated cells through cytochrome c release from mitochondria to cytoplasm, and cleavage of caspase-3 and -9. Investigation of the effect of quinalphos on the expression of antioxidant- and apoptosis-related genes showed that most of the antioxidant genes were down-regulated, while apoptotic genes were up-regulated. Therefore, we propose that the toxicity of quinalphos is mediated by increasing generation of ROS, modulation of expression of major antioxidant genes that have considerable role in mitigating oxidative stress, and the induction of apoptosis.