Dose-dependent effects of ethanol on lead-induced oxidative stress in rats

This study explored the dose-dependent effects of ethanol ingestion during co-exposure with lead in rats. Lead was administered orally, once daily at a dose of 10 mg/kg whereas ethanol was given in drinking water at 3 different doses: 1%, 2%, and 5% along with lead. The exposure continued for 3 months, after which the animals were decapitated and various biochemical assays were carried out. The results show increased oxidative stress in animals co-exposed to lead and ethanol compared with either lead or ethanol alone. A significant decrease in blood δ-aminolevulinic acid dehydratase activity, glutathione (GSH), GSH peroxidase, adenosine triphosphatase, and catalase but a significant increase in reactive oxygen species, oxidized GSH, thiobarbituric acid reactive substance, and intracellular calcium was noted in lead and ethanol co-exposed animals. The changes were found to be dose dependent in lead plus ethanol exposed animals. Decrease in glucose-6-phosphate dehydrogenase activity in blood was noted, with no significant changes in liver and kidney. Aldehyde dehdrogenase activity decreased significantly in animals exposed to either lead or ethanol but a pronounced depletion was seen in rats co-exposed to lead and ethanol (5%). The results suggest that the combined exposure to lead and ethanol leads to increased oxidative stress and possible initiation of apoptosis in rats.