Molecular and Biochemical Evidences for Beneficial Effects of Zinc Oxide Nanoparticles in Modulation of Chlorpyrifos Toxicity in Human Lymphocytes.

Chlorpyrifos (CP), an acetylcholinesterase (AChE) inhibitor, is used throughout the world as an insecticide in agriculture and an eradicating agent for termites around homes. In the present study, we examined the protective role of zinc oxide nanoparticles (ZnO NPs) in human CP-treated lymphocytes. Lymphocytes isolated by Ficoll and exposed to 75 µg/mL CP either alone or in combination with logarithmic doses of ZnO NPs (0/1, 1, 10, 100 µg/mL). After a 3-day incubation period, the viability and oxidative stress markers were determined. Then, the levels of tumor necrosis factor-α (TNF-α), as an inflammatory index along with AChE activity and cell death were evaluated. Our results showed that incubation with CP significantly increases the percent of cell death, activities of caspase-3 and -9, level of TNF-α and also promotes the levels of biomarkers which play important role in oxidative stress. On the other hand, the activity of AChE and levels of the total antioxidant power (TAP) decreased in CP-treated lymphocytes. In contrast, lymphocytes treated with different concentrations of ZnO NPs showed a significant decrease in the percent of mortality as well as the levels of TNF-α, as compared with CP-treated lymphocytes. Besides, ZnO NPs increased the levels of AChE and TAP at 1 µg/mL. In conclusion, the results indicate the protective effects of ZnO NPs in the prevention of cytotoxic activity of CP in the lymphocytes.