Histomorphological changes and Glutamate levels in Fluoride and Arsenic Induced Injury to Hippocampus and Cerebral Cortex in Wistar rats and assessment of the ameliorating effects of Ginkgo biloba

Abstract

Introduction: Fluoride and Arsenic are the inorganic contaminants existing in drinking water, and their consumption can have serious consequences. The present study was aimed to investigate the effects of Fluoride and Arsenic alone and in combination on learning and memory ability, Histomorphological changes, Glutamate levels, mGluR5 gene expression and Total protein expression in the Hippocampus and Cerebral cortex, in Fluoride & Arsenic exposed Wistar rats and the ameliorating effect of Ginkgo biloba in these rats. Materials and methods: 64 one-month-old male Wistar rats were randomly assigned to one of Eight Groups: I-Control, II-Fluoride (Fl), III-Arsenic (As), IV-Fluoride+Arsenic, V-Extraction of Ginkgo Biloba (EGB), VI-Fl+EGB, VII-As+EGB, VIII-Fl+As+EGB. The Potable water has given to the Control group of rats and the remaining group of rats were given water containing 120 ppm of Fluoride and 70 ppm of Arsenic for 180 days. Hebb William's maze and T mazes were used to assess learning and memory. H&E, Cresyl Violet, and Luxol Fast Blue staining were used to evaluate Histomorphological changes in the Hippocampus and Cerebral cortex. Results: The learning and memory ability has declined in Fluoride and Arsenic-treated rats when compared to Controls and EGB-treated rats. Histomorphological changes in the Hippocampus and Cerebral Cortex, Neurons in the Control and EGB-treated groups showed more viable neurons with clear nuclei and cytoplasm, whereas neurons in the Fluoride and Arsenic-treated group of rats had darkly stained and irregularly arranged pyramidal and granular cells and evidence of Karyopyknosis. Combined Fl+As and an Individual Arsenic exposed group of rats showed numerous vacuoles in the Hippocampus and Cerebral cortex. Extractions of Ginkgobiloba treated group of rats have shown less affected pyramidal and granular cells and no vacuoles. Conclusion: Long-term combined exposure to Fluoride and Arsenic and Arsenic alone has negative effects on the brain, resulting in decreased learning and memory ability and Histomorphological changes when compared to the effects of Fluoride and Control. EGB has shown ameliorating effects on Fluoride and arsenic-exposed brain tissue and learning and memory ability. Fluoride and Arsenic may cross the blood-brain barrier and collect in the rat’s xvii brain. Fluoride and arsenic, either alone or combined in drinking water may impair spatial learning and memory ability and lead to mild cognition impairment. The reduction of glutamate levels and mGluR5 mRNA and protein expressions in the hippocampus and cortex may be responsible for impairments in learning and memory ability. Ginkgo Biloba has potent effects on the central nervous system. Ginkgo Biloba may protect neurons against ischemia, enhance cognition, preserve hippocampal mossy fibers, improve neural plasticity, and prevent the cognitive deficits that result from stress or traumatic or chemical brain injury.