Abstract
Sprague Dawley albino rats were treated with 30, 45, and 75 mg NaF/kg body weight/day respectively for 20 days and 35 days to study neurotoxic effect of fluoride. The control rats were injected with double distilled water 1cc/kg body weight/day. The animals were sacrificed and the cerebrum was analysed for neurodegenerative anomalies. The adenomatous foci were formed in the cerebral cortex containing degenerating glial cells. The glial cells became vacuolated and showed hyperchromatization of nuclei in brain of rats treated with 30 mg NaF/kg body weight/day. The chain formation of the disintegrated glial cells, senile plaque and large globose shaped neurofibillary tangle inside the perikaryon in cerebral cortex were observed in rats treated with 45 mg NaF/kg body weight/day. An elongated highly chromatolytic region with large number of vacuolated cells was visible. In some neurons, neuroplasm become hyperchromatic, fragmentation and apoptosis of nuclei was prominent. Pleomorphic, irregular glial cells showed necrosis, the cerebral cortex exhibited diffused haemorrhages in rats of 75 mg NaF dose group. The results of present study revealed a fairly consistent pattern of adverse effects by fluoride on cerebral neuropathology, which may be a cause of neurological sequelae and abnormal neuro-behavioural patterns in fluorosis.