Changes of reactive oxygen species level and mitochondria fission-fusion hi cortical neurons of rats with chronic fluorosis

：Objective To investigatethe changes of reactive oxygen species(ROS) level and mitochondria fission-fusion-balancein cortical neurons of rats with chronic fluorosis and reveal the correlation betweenthese two factors. Methods One hundred and twenty rats were randomly divided into 3groups(control group, low-dose fluorosis group, high-dose fluorosis group) and 40 ratswere in each group according to body weight and the experiments were carried out for 3months or 6 months. The rats were fed with different concentrations of fluoride (NaF) toestablish fluorosis models. Controls were fed with tap water( 0.05). Furthermore, the increases in both ROS level andabnormal numbers of mitochondria were significant observed in the cortical neurons oflow-dose fluorosis group (63.02 ± 8.15, 49.33 ± 8.61) and high-dose fluorosisgroup(65.60 ± 7.40,53.10 ± 6.95) as compared with the control group (25.26 ± 6.41,20.26± 6.41) at the experimental period of 6 month (all P < 0.05). The abnormal numbers ofmitochondria correlated with ROS level(r = 0.93,0.81, all P < 0.05). Conclusions Takingexcessive amount of fluoride results in high level of oxidative stress and impaired thebalance of mitochondrial fission-fusion,which is dependent on the feeding times and dosesof fluoride. The mechanism of the mitochondrial abnormalities might be associated with thehigh level of oxidative stress induced by chronic fluorosis.