OBJECTIVE: To explore the effect of endemic fluoride poisoning caused by coal burning on the oxidative stress in rat testis.
METHODS: Totally 40 male SD rats were equally randomized into four groups control group, low fluorosis group, middle fluorosis group, and high fluorosis group. Rats in all three fluorosis groups were fed with corn dried by burning coal obtained from endemic fluorosis areas with high fluoride, and thus the animal models of fluorosis were established. After 120 and 180 days, all the rats were sacrificed. Testis tissues were stained with hematoxylin eosin and observed under light microscope. The malonaldehyde (MDA) content, superoxide dismutase (SOD) activity, total nitric oxide synthase (TNOS), and inducible nitric oxidase synthase (iNOS) were measured by biochemical methods in the testis tissues. The content of NaF in testis was measured by fluorine selective electrode.
RESULTS: The rat fluorosis models were successfully established. The fluoride content in testis was significantly increased in all the fluorosis groups(P<0.01). Testicular structures were damaged in all of fluoride groups. The TNOS, iNOS activities, and MDA content of each fluoride group were significantly higher than that of the control group on day 120 and 180 (P<0.05 or 0.01 ). The TNOS, iNOS activities, and MDA content significantly increased in a dose dependent manner (P<0.05 or 0.01). The SOD activities significantly decreased in all the fluoride groups (P<0.05 or 0.01).
CONCLUSIONS: Endemic fluoride poisoning caused by coal burning can cause disorders in the oxidative system and antioxidative system in rat testis. The oxidative stress may play an important role in the fluorides induced reproductive toxicity in male rats.