Abstract

Brain tissues for neurohistopathological study were obtained at autopsy from albino rabbits that had been subcutaneously injected for 15 weeks with 0, 5, 10, 20, and 50 mg sodium fluoride in 1 mL of aqueous solutions/kg bw/day. Neuropathological changes occurred with loss of the molecular layer and glial cell layer in the brain tissues of rabbits exposed to the three higher fluoride doses. The Purkinje neurones exhibited chromatolysis and acquired a “ballooned” appearance. Nissl substance showed various degrees of decrease and even complete loss. Fragmented particles were retained in the perinuclear zone. The perikaryon showed vacuolization, and spheroid bodies were present in the neoplasm. These cytoplasmic inclusions appeared as various sized ovoid bodies or elongated eosinophilic masses due to which the nucleus was shifted to the periphery. These neurotoxic changes in the brain suggested that there was a direct action of fluoride upon the nerve tissue which was responsible for central nervous system problems such as tremors, seizures, and paralysis indicating brain dysfunction seen at the two highest doses.

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