Fluoride 2002; 35(3): 197-203

Brain lipid peroxidation and antioxidant systems of young rats in chronic fluoride intoxication

YM Shivarajashankara, AR Shivashankara, P Gopalakrishna Bhat, S Hanumanth Rao

Department of Biochemistry, MR Medical College, Gulbarga-585105, Karnataka, India. E-mail: shivrajsym@yahoo.com

SUMMARY: A study was made of the effect of fluoride on oxidative stress in rats during their early stages in life. Wistar albino rats were exposed to 30 ppm and 100 ppm fluoride (from sodium fluoride) in drinking water during the last one week of intrauterine life and then up to ten weeks after birth. Oxidative stress was evaluated by the assays of malondialdehyde and antioxidants in brain homogenates. Malondialdehyde (MDA), the marker of extent of lipid peroxidation, was elevated in the brain of rats treated with 100 ppm fluoride but was without change in rats treated with 30 ppm fluoride. Levels of total glutathione, reduced glutathione (GSH), and ascorbic acid (vitamin C) were elevated in 30 ppm fluoride-treated rats, while these levels decreased in 100 ppm fluoride-treated rats. The activity of glutathione peroxidase (GSH-Px) was elevated significantly in both 30 ppm and 100 ppm fluoride-treated rats. Glutathione S-transferase (GST) activitiy in the brain increased with 30 ppm and 100 ppm fluoride, and greater elevation occurred at 30 ppm. These results suggest that fluoride enhances oxidative stress in the brain, thereby disturbing the antioxidant defense of rats. Increased oxidative stress could be one of the mediating factors in the pathogenesis of fluoride toxicity in the brain.

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