Diazinon toxicity in hepatic and spleen mononuclear cells is associated to early induction of oxidative stress

Diazinon is an organophosphorus pesticide, which may have potential toxic effects on the liver and immune system; however, the underlying mechanisms remain mostly unidentified. This work is aimed at evaluating the oxidative stress and cell cycle alterations elicited by low-dose diazinon in a rat liver cell line (BRL-3A) and spleen mononuclear cells (SMC) from Wistar rats. Diazinon (10-50 mu M) caused early reactive oxygen species (ROS) generation (from 4 h) as well as increased O-2(center dot-) level (from 0.5 h), which led to subsequent lipid peroxidation at 24 h, in BRL-3A cells. In SMC, diazinon (20 mu M) produced similar increases in ROS levels, at 4 and 24 h, with the highest O-2(center dot-) level being found at 4 h. Low-dose diazinon induced G1-phase arrest and cell death in hepatic cells and SMC. Therefore, diazinon could affect the liver and the immunological system through the premature oxidative stress induction.