Abstract:

Abstract:Objective  To observe the influence of fluoride in the pathological changes of incisor and the changes of physiological indicators of the rats with type 1 diabetes mellitus,and to clarify the effect of fluoride on process of diabetes mellitus. Methods 54 male Wistar rats were divided into control group (n=18),10 mg/kg/d F－group(10 mg　F－) (n=18)and 20 mg/kg/d F－group(20 mg　F－) (n=18).Fluoride was fed by gavage,1 month later 12 rats in each group were selected and treated with single intraperitoneal injection of 50 mg?kg-1 STZ to induce type 1 diabetes mellitus (used as STZ control group,10 mg　F－+STZ group,and 20 mg　F－+STZ group), then  the remaining 6 rats were fed with fluoride for 4 weeks(used as normal control group,10 mg　F－ group,and 20 mg　F－ group). In the experimental period,the changes of blood glucose were measured by glucose meter weekly,and the photograph was taken to follow teeth progressive changes. Before the end of experiment,intraperitoneal injection of insulin was performed to test the insulin sensitivity of the rats by insulin tolerance test(ITT).Results The rat dental face in 10 mgF－and 20 mg F－ groups gradually shifted from yellow to pale and turned to rough,uneven coloring,part of the teeth with white opaque changes,showing dental fluorosis alteration.Compared with normal control group,the rats in simple fluoride poisoning group had no change in weight,but after intraperitoneal injection of STZ,the weights of the rats in three groups showed downward trend,especially in 20 mg F－group,but there was no significant difference (P>0.05);after STZ induction the blood glucose levels were increased significantly (P<0.05) compared with normal control group;and the blood glucose level in 20 mg F－+STZ group had obviously change,but  there was no significant difference (P>0.05) compared with STZ control group.The ITT results showed that the glucose levels in 20 mg F－ group were significantly higher than those in normal  control group (P<0.05) at 0.5,1 and 2 h,while the glucose level in 10 mg F－group was elevated,but the difference was not statistically significant (P> 0.05).Conclusion High dose of fluoride can cause short-term dental fluorosis,aggravate the diabetes-induced body weight loss and blood sugar increasing,and decrease the insulin sensitivity in rats.

Key words:  fluoride;dental fluorosis;diabetes mellitus, experimental;insulin sensitivity