TOXIC EFFECTS OF FLUORIDE ON REPRODUCTIVE ABILITY IN MALE RATS: SPERM MOTILITY, OXIDATIVE STRESS, CELL CYCLE, AND TESTICULAR APOPTOSIS

To investigate the effects of sodium fluoride (NaF) on sperm motility, oxidative stress, and apoptosis in the testes, male Wistar rats were exposed to 1.0, 2.0, and 3.0 mg NaF/kg bw/day by intragastric gavage for 90 days. Sperm motility was significantly inhibited, especially at the lower F intake level. Significant increases in oxidative stress with elevated malondialdehyde occurred in the 1.0 mg NaF group and increased hydrogen peroxide in the 2.0 mg NaF group. Compared with the control group without NaF, the cell percentage in G0/G1 phase increased significantly, whereas it decreased significantly in S phase. On the other hand, the percentage of cells in G2/M phase was similar to that of the control. In the 2.0 and 3.0 mg NaF groups, a significant increase in testicular cell apoptosis was observed. Thus, especially at a comparatively lower level of exposure, F exhibits toxic effects on reproductive function in the form of decreased sperm motility, enhanced oxidative stress, and increased apoptosis, although the latter does not appear to be directly connected with the increased level of oxidative stress.