The action of fluoride (F) and aspirin (acetylsalicylic acid, ASA) administered separately and together on oxidative stress parameters and on F excretion in rats was studied over a period of six weeks. Thirty adult male Wistar rats were divided into five equal groups of six each: (I) controls receiving tap water; (II) controls receiving intragastrically 1 mL of tap water (once a day); (III) animals receiving 25 mg F/L in their drinking water; (IV) animals receiving 35 mg ASA/kg bw/ day; (V) animals receiving 25 mg F/L in drinking water and 35 mg ASA/kg bw/day. In rats treated only with fluoride the F excretion in urine significantly increased in an exposure time-dependent manner and decreased both in rats treated with ASA and co-exposed to ASA and F. In animals treated with ASA alone, the activity of glutathione peroxidase (GPx) and the concentrations of glutathione (GSH) and thiobarbituric acid reactive substances (TBARS) increased in brain, liver and blood, whereas the activity of catalase (CAT) decreased in liver and erythrocytes, but increased in liver. In rats exposed to F alone the concentration of GSH and the activities of GPx and CAT decreased, whereas the concentration of TBARS significantly increased in liver, brain, kidney and blood. In rats co-exposed to F and ASA, the concentrations of GSH and TBARS and the activities of GPx and CAT (except in liver) were higher than in animals receiving only F.
An interesting further observation was that ASA decreases F excretion in urine.