Abstract: ObjectiveTo study the effects of fluoride on the expressions of caspase-3 and caspase-9 during apoptosis of kidney cells of rats.MethodsForty eight Sprague-Dawley (SD) rats were randomly divided into control group,low does group,medium does group,high does group,and then were given drinking-water with 0 mg/L,50 mg/L,100 mg/L,and 200 mg/L sodium fluoride,respectively,for 120 days.Urinary fluoride content was measured.The rats were sacrificed and their body weight and kidney organ weight were weighed.Kidney organ coefficient was calculated and renal pathological slices of the rats in high does group were observed.In high does group,caspase-3 and caspase-9 were measured with immunocytochemistry.ResultsThe body weight of the rats in treatment groups was significantly lower than that of the control group(P<0.01).Kidney organ coefficient was significantly lower for the rats in medium does group than that of the control group(P<0.05).The urinary fluoride content was significantly lower in all rats with fluoride exposure than in the rats in the control group(P<0.01),with a dose-effect relationship between urine fluorine and fluoride concentration (r=0.925,P<0.01).Enlarged disordered renal tubule structure,degeneration,necrosis,void and atrophy of glomerular endothelium and tubular epithelium were observed in the rats treated with fluoride.The average optical density values of caspase-3 and caspase-9 were significantly higher in the rats of medium dose fluoride group(0.37±0.05 and 0.40±0.02) and high dose group(0.41±0.07 and 0.46±0.06) compared to those of the control group(P<0.01 for all).ConclusionFluoride increases the expressions of caspase-3 and caspase-9,which induces apoptosis of kidney cells.