Effects of quercetin, fish omega-3 fatty acids and melatonin on the changes in cerebrum and cerebellum in rats exposure to cadmium

Cadmium is one of the toxic heavy metals, which was discovered in 1817. It is found in artificial fertilizers, cigarette smoke, batteries. Organisms are exposed to cadmium through air and water. It may accumulate in tissues since there is no specific cadmium elimination system in the body. Central nervous system is one the sites where chronic cadmium accumulation occurs. We investigated toxic effects of cadmium on rat cerebrum and cerebellum and protective effect of quercetin, fish omega-3 fatty acids and melatonin against these effects.52 wistar Albino male rats were divided into six groups: 1) Control group (1 mg/kg saline), 2) Cadmium group (1 mg/kg), 3) Cadmium (1 mg/kg) + Melatonin (25 mg/kg) group, 4) Cadmium (1 mg/kg) + Quercetin (270 mg/kg) group, 5) Cadmium (1 mg/kg) + fish n-3 fatty acid (400 mg/kg) group, 6) Cadmium (1 mg/kg) + Quercetin (270 mg/kg) + fish n-3 fatty acid (400 mg/kg) group. Melatonin was injected intraperitoneally, but all other reagents were administered intragastrically for six weeks.All rats were sacrificed under anesthesia at the end of the exposure period, cerebrums and cerebellums were removed. Left hemispheres of cerebrum and cerebellum from each rat were used for biochemical analysis and right hemispheres were used for morphological evaluation. After routine tissue preparation, cerebrum and cerebellum sections were stained with cresyl violet acetate. Activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) and malondialdehyde (MDA) levels were determined spectrophotometrically.Light microscopic evaluation of the cadmium group revealed a marked decrease in the number of cells in external granular lamina and external pyramidal lamina of cerebral cortex along with picnotic and hyperchromatic changes in the nuclei of neurons in the hippocampal region. There was no histological change in stratum moleculare, stratum granulosum and white matter of cerebellar tissue, however, a decrease in the number of Purkinje cells was noted. SOD activity was found to be increased in cadmium group except cerebral tissue. GSH-Px activity and MDA levels were increased in all tissues in cadmium groupWe concluded that cadmium causes morphologic and biochemical injury in rat cerebrum and cerebellum; this injury may be partially prevented by giving antioxidant-acting quercetin, fish n-3 fatty acids and melatonin.