環境および分析毒性学

Neuroprotective Role of Quercetin against Arsenic Induced Oxidative Stress in Rat Brain

Abstract

Shveta Nirankari, Rozy Kamal and Devinder K Dhawan

Arsenic, a poisonous metalloid, is ubiquitous in the environment, and affects nearly all organ systems of animals including humans. The present study was conducted to understand the protective role of quercetin, a natural flavonoid on arsenic-induced oxidative damage in rat brain. Forty male Sprague Dawley rats, aged between 7 to 8 weeks and weighing 150-200 g were divided into four groups viz. normal control, arsenic treated, quercetin treated and arsenic + quercetin treated. Rats in normal control group were given normal food and drinking water. Rats in arsenic treated group were given arsenic daily in the form of sodium arsenite (NaAsO2) in drinking water at a dose of 100 mg/l. Rats in the quercetin treated group were given quercetin, dissolved in distilled water, orally everyday through intubation gavage at a dose of 50 mg/kg body weight. Rats in the combined arsenic + quercetin treated group were given arsenic and quercetin in a similar manner as was given to rats belonging to arsenic and quercetin treated group. After 2 months of treatment, antioxidant defense status and changes in the brain histo-architecture were assessed. A significant increase in the levels of lipid peroxidation and a decrease in reduced glutathione levels were observed in the brain of arsenic treated rats, when compared to the normal controls. Further, decrease in the activities of antioxidant defense enzymes such as superoxide dismutase, glutathione peroxidase, glutathione-s-transferase and glutathione reductase, as well as the activity of enzyme nitric oxide synthase were detected in arsenic treated group, which however were restored to normal levels upon simultaneous treatment with quercetin. Brain tissue of arsenic treated rats, also showed changes at the histo-architectural level which were normalized on simultaneous treatment with quercetin. The study, therefore, reveals that quercetin shall prove to be beneficial in containing the neuro-toxic effects of arsenic.