Effects Of Fluoride On The Blood-testis Barrier And Its Mechanism Study In Adult SD Rat

[Objective]The early study in our lab have shown that the ultrastructure of blood-testis barrier(BTB)in the mice exposed 100 mg/L by drinking water for 2 months were damaged.And the expression level of associated genes and proteins were also changed.To understand more clearly,provide further theoretical basis for fluorine of reproductive toxicity,this paper carried out a more comprehensive study.[Methods]60 healthy and adult SD rats randomly divided into 5 groups,including control group,positive group and fluoride treated groups that exposed to 25,50,100 mg/L NaF by drinking water.During exposure periods,the food and water intake,weight in rat were regularly observed and recorded.At the 29th day,3mg/Kg was injected in 0.1%CdCl2 for positive group.At the end of the exposure period,effects of fluoride on the structure and function of BTB were observed by biotin tracer,transmission electron microscope(TEM).The expressions of BTB associated proteins and cytokines were detected by western blotting and ELISA respectively.[Results]1.Compare to control group,there is no significantly difference in the body weight and organ coefficient of testis and epididymis of NaF treated groups and positive group.2.The ultrastructure changes of the BTB in testes of rat in different groups were observed by TEM.The picture of the control group showed a typical BTB.Local disassembly of the TJ,expanded endoplasmic reticulum(ER)was observed in the positive group.Compared with control groups,the structure of BTB was damaged by fluoride in 50 and 100 mg/L group.3.Biotin tracer results:in the positive control group,the green fluorescence could be seen from the seminiferous tubules to the lumen.There were no obvious changes in the low fluoride group compared with the normal control group.Bright green fluorescence can be observed in the interstitial space and near lumen of the seminiferous tubules in the fluoride group,and the green fluorescence in the lumen is less.In the fluoride group,the green tubules showed little green fluorescence on the tube wall and lumen side,and more green fluorescence was seen in the lumen.4.The expression level of BTB relative proteins Occludin,CAR,ZO-1,N-cadherin,a-catenin,?-catenin and Cx-43 in testis of rat were evaluated by using western-blotting technology.Compared with the control group,the majority of the 3 fluoride treated rats had no significant changes in the expression of the blood testis barrier component protein,except that the expression of ?-catenin decreased significantly.5.The result of ELISA test found that,compared with control,the expression of IL-la in fluoride treated groups were extremely significantly increased.The level of TGF-?3 and TNF-a in low medium fluoride groups were increased significantly,while there is no statistical difference in each high fluoride groups.[Conclusion]Fluoride disturb the structure and function of BTB,and decrease the expression of BTB associated protein ?-catenin.These changes may also be associated with an increase in the expression of the level of IL-la.