Protective effect of quercetin and thymoquinone against genotoxicity and oxidative stress induced by ZnO nanoparticles in the Wistar rat model

Zinc oxide nanoparticles (ZnO-NPs) are increasingly used in a variety of consumer and other commercial products. Hence, man faces the risk of exposure to ZnO-NPs and the consequent adverse health effects. Mitigation/prevention of such effects using natural products has drawn the attention of scientists. Therefore, the aim of the present study has been to find the toxic effects associated with exposure to ZnO-NPs, and the protective role of the phytochemicals thymoquinone (TQ) and quercetin (QCT) in the rat model. ZnO-NPs were administered to male Wistar rats through oral route; TQ / QCT was concurrently administered through intra-peritoneal route. The response in the animal was analyzed adopting chromosomal aberration test, micronucleus test, and comet assay of bone marrow cells to assess the genotoxicity, and biochemical assays of superoxide dismutase (SOD), catalase (CAT), lipid peroxidation (LPO), total extractable protein of liver, and reduced glutathione (GSH) of liver homogenate to monitor the changes in the antioxidant defense mechanism in response to the oxidative stress. Treatment of 300 mg/kg body weight (bw) of ZnO-NPs produced adverse effects on all aspects analyzed viz., structural chromosomal aberrations, micronuclei formation, DNA damage, SOD, catalase, lipid peroxidation, GSH, and extractable total protein of liver. Co-treatment of TQ / QCT offered protection against the toxicity induced by ZnO-NPs. The most optimum doses of TQ and QCT that offered the best protection were 18 mg/kg bw and 500 mg/kg bw, respectively. The study reveals that TQ / QCT supplementation is beneficial in the context of toxic effects of ZnO-NPs.