Oxidative Stress Biomarkers in the Freshwater Fish, Heteropneustes fossilis (Bloch) Exposed to Sodium Fluoride:Antioxidant Defense and Role of Ascorbic Acid

The present study highlights fluoride ‑induced toxicity and the protective role of ascorbic acid in the liver and ovary of freshwater fish, Heteropneustis fossilis. The fish specimens were exposed to different concentrations (35 mg F/L and 70 mg F/L) of fluoride. Parameters related to oxidative stress were studied at the end of the experiment. The biomarkers selected for the study were thiobarbituric acid reactive substances for assessing the extent of lipid peroxidation (LPO) and antioxidant defense system such as reduced glutathione (GSH), superoxide dismutase (SOD) catalase (CAT) glutathione peroxidase (GPx), and glutathione S‑transferase (GST) activities. The fluoride exposure significantly elevated the level of LPO, CAT, SOD, and GST in the tissues of treated group as well as modulated the activities of GSH and level of GPx after exposure as compared to the control. A significant decrease in GPx activity was found in these tissues suggesting that fluoride exposure increases the level of free radical, as well as CAT activity. Pre‑ and post treatment with ascorbic acid decreased the LPO, SOD, CAT, GST level, and increased GSH, GPx levels in the liver and ovary.