Changes in Antioxidants in the Brain of Fluoride-Treated Rats

Abstract

In recent times, fluorosis is gradually becoming a severe problem throughout the globe due to toxic effects of fluoride (F) on plants and animals. Natural geological sources and increased industrialization have contributed greatly to the increasing incidence of fluoride-induced human and animal toxicities. Adverse effects are mainly through the attenuation of antioxidant defense mechanism and chelation of enzymatic cofactors. This present study was carried out to investigate the changes that occur on antioxidants in the brain of male wistar rats after sub-chronic fluoride exposure at varying doses (10 ppm, 20 ppm and 40 ppm). Twenty-four (24) Male Wistar rats with average weight of 120 g were distributed into 4 groups according to dose administration (Control; 10 ppm, 20 ppm and 40 ppm) of 6 animals each. The control groups were given only distilled water while the Test groups were given sodium fluoride at doses mentioned above for 30 days. Overnight fasted animals from each group were sacrificed on the 30th day and the brain removed for studying the antioxidant activities. Catalase (CAT), reduced glutathione (GSH), glutathione peroxidase (GPx) and glutathione-s-transferase (GST) were measured from the homogenized brain supernatants. Results showed that CAT and GPx decreased in activity in respect to the dose being applied. Decrease in glutathione peroxidase activity was highest at 20 ppm and 40 ppm while Catalase activity showed a decrease at 10 ppm. Reduced glutathione GSH activity increased in the 10 ppm and 20 ppm but decreased at 40 ppm. Other antioxidant activities measured displayed similar trend with much decrease at higher doses. From our results we can say that fluoride toxicity causes changes in antioxidants level. The implications of these findings are herein discussed.