Exposure to Low Doses of Endosulfan and Chlorpyrifos Modifies Endogenous Antioxidants in Tissues of Rats

Abstract

Two experiments were conducted in male SD rats (225-250 g) to determine changes in the activities of endogenous antioxidants superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX) and concentrations of glutathione (GSH) in tissues after exposure to low doses of endosulfan and chlorpyrifos using a whole body exposure technique. In both experiments, 6 rats/group were exposed 3 hr/day, 5 days/week for 30 days to: 0 (control), 5, 10, 20, 40 and 60% of LD50 of either pesticide in 50% ethanol; actual concentrations were: endosulfan = 0, 0.5, 1.0, 2.0, 4.0, 6.0 mg/250 g body weight; chlorpyrifos = 0, 1.9, 3.8, 7.6, 15.2, and 22.8 mg/250 g body weight. Endosulfan decreased erythrocyte SOD by 21% in all groups and chlorpyrifos increased SOD by 18% in groups 40 and 60. Liver SOD was 12%-20% lower after endosulfan exposure; lung SOD was altered: endosulfan decreased activity by 21% and 51% and chlorpyrifos by 58 and 75% in the 40 and 60 groups, respectively (P < or = 0.05). Both pesticides increased plasma GPX activity at lower levels and reduced it by 26% and 19% in groups 40 and 60, respectively (P < or = 0.05). Liver GPX increased in the 60 group and lung GPX declined between 20% and 38% after endosulfan exposure. GSH in the liver and lung: endosulfan reduced GSH by about 30% at lower levels and increased by 41% or 70% at higher levels; chlorpyrifos decreased GSH by 28-40% in 20 and 60 groups, respectively (P < or = 0.05). Exposure to low, increasing levels of endosulfan and chlorpyrifos can differentially modify endogenous antioxidants SOD, GPX and GSH, which may lead to the development of oxidative stress in some tissues.

The Propolis Effect on Chlorpyrifos Induced Thyroid Toxicity in Male Albino Rats

“…These results are in agreement with who reported enhancement of MDA production, decrease in reduced glutathione content, glutathione-S-transferase and catalase activities in rat tissues that treated with CPF [45]. Also, other previous studies have been reported accumulation of lipid peroxides in rat liver after exposure to acute dose of cholrpyrifos and kidney while, repeated doses of CPF increased LPO levels as well as decreased antioxidant enzymes in rat liver and lung [46][47][48][49].…”

Short- and long-term exposure to low levels of pesticide and flavonoid mixtures modify endogenous antioxidants in tissues of rats

“…The modulation of SOD activity by pesticides is reported to be variable with low doses of some pesticides not altering, but higher doses increasing activity in the liver and other tissues. [11,13,19,20] More recently, Gao et al [21,22] have shown that feeding of flavonoid rutin at 2.25 g/kg body weight to mice or rats did not alter hepatic Zn, Cu SOD activity, but significantly decreased catalase activity along with an increase in total antioxidant status in the liver. The present data suggest that the increase in liver SOD activity after long-term feeding of FM with and without PM exposure may be a result of increased intracellular free radical oxygen accumulation that may have been generated by auto-oxidation and/or metabolism of FM by the drug metabolizing Phase I enzyme cytochrome 450 1A1.…”

Pesticide use and colorectal cancer risk in the agricultural health study

“…45 Chlorpyrifos has been found to modify endogenous antioxidants in rats, possibly leading to the development of oxidative stress. 46 A case-control study reported increased risk of non-Hodgkin's lymphoma 47 and glioma 48 among male farmers exposed to chlorpyrifos in the United States. In a previous analysis of cancer among chlorpyrifos users in the Agricultural Health Study cohort, we reported an increased risk of rectal cancer consistent with our current findings, as well as excesses for cancers of the lung and brain.…”