Abstract: The experiment was conducted to study the effects of fluorine on ultrastructure of mature sperm in mice epididymis, and provide the basis for reproductive toxicity study and detection induced by fluorine. 20 healthy male Kunming mice were randomly distributed into 4 groups including the control group(distilled water), low dose fluoride (25 mg/L NaF) in their drinking water,middle dose fluoride (50 mg/L NaF)and high dose fluoride (100 mg/L NaF)group. After 45 days exposure, all mice were sacrificed by cervical dislocation and cauda epididymidis were collected for further analysis. 2.5% glutaraldehyde had been used to fix cauda epididymidis, the ultrastructure change of normal and different doses of fluorosis mice sperm were observed by the transmission electron microscope. Compared with the control group, plasmalemma around the head of sperm fractured, plasmalemma partly had fallen off, some of the mitochondria swelled and the structure of mitochondria was vague in low dose fluoride group. The plasmalemma of mitochondria had fallen off, acrosome partly lost, the figure of mitochondria was irregular and mitochondrial intracristal space was enlarged in middle dose fluoride group. For high dose fluoride group, the plasmalemma of mitochondria had fallen off, irregularly arranged mitochondrion acrosome dilated, mitochondrial vacuolization and mitochondrial cristae was vague. The results showed that varying degrees of changes had occurred in the ultrastructure of both the sperm head and the middle of sperm tail, especially mitochondria displayed obvious structural abnormalities, and the higher the fluorine concentration, the more dramatic changes had taken place on the ultrastructure of epididymal mature sperm in male mice.

Key words: mice; fluorosis; sperm; ultrastructure