ABSTRACT
A subchronic toxicity study was carried out to determine the glyphosate-induced histopathological changes in the stomach, liver, kidney, brain, pancreas and spleen of rats and the attendant ameliorative effect when pretreated with zinc at the dose rate of 50 mg/kg body weight. The rats were exposed to two doses of the glyphosate (375 and 14.4 mg/kg body weight) for the period of 8 weeks which was the duration of the study, and some groups were exposed to the glyphosate after pretreatment with zinc. The histopathological changes recorded during the study were only in the rats exposed to the glyphosate at the dose rate of 375 mg/kg body weight except the vacuolation encountered in the brains and haemosiderosis in the spleens of rats exposed to zinc alone. Degenerated mucosal epithelial cells which involved the muscularis mucosa and the glands in the stomachs of rats were seen microscopically. Hepatic cells degeneration especially at the portal areas of the livers of rats was observed. The histopathological examination of the kidneys showed glomerular degeneration, mononuclear cells infiltration into the interstices of the tubules and tubular necrosis. The conspicuous changes seen in the brains were neuronal degeneration. Pancreatic acinar cells were degenerated while the spleen of the rats showed depopulated splenic cells in both the red and the white pulps. It was concluded that zinc supplementation in rats prior to glyphosate exposure ameliorated the histopathological changes observed in the stomach, liver, kidney, brain, pancreas and spleen with no observable alteration in the histoarchitecture in the organs of the zinc-supplemented rats.
ABSTRACT
A subchronic toxicity study was carried out to assess hepatic and renal functions of rats during oral exposure to glyphosate with zinc for the period of 8 weeks. Forty-eight Wistar rats used for the study were randomized into six groups of eight Wistar rats each, and each group had equal number of male and female Wistar rats. The Wistar rats administered with distilled water at 2 ml/kg body weight served as the control group (DW); others were administered with zinc at 50 mg/kg body weight (Z) group, glyphosate at 375 mg/kg body weight (G) group, a combination of zinc and glyphosate at 50 and 375 mg/kg body weight, respectively (Z + G), group, glyphosate at 14.4 mg/kg body weight (GC) group, and a combination of zinc and glyphosate at 50 and 14.4 mg/kg body weight, respectively (Z + GC), group. At the end of the study, blood samples were collected from each rats; from which, sera samples were obtained and assayed for total protein, albumin, alanine and aspartate aminotransferases, alkaline phosphatase, Na+, K+, Cl-, [Formula: see text], Ca2+, [Formula: see text], urea and creatinine using autoanalyzer, and globulin was calculated. The albumin concentration was significantly high (p < 0.05) in GC group compared to DW group, and this change was ameliorated following supplementation with zinc. The total protein and globulin concentrations did not differ significantly between the groups (p > 0.05), and the relative changes were ameliorated by supplementation with zinc. The alkaline phosphatase activity was relatively low in GC group; however, supplementation with zinc in Z + GC group made it to be significantly high (p < 0.05) compared to GC group. The alanine and aspartate aminotransferases in G and GC groups were relatively high compared to DW group, which were ameliorated by supplementation with zinc. The relatively low Ca2+ concentration in G and GC groups compared to DW were ameliorated in Z + G group, and it was significantly high in Z + GC group at p < 0.01 compared to DW, p < 0.001 compared to G and GC groups and p < 0.05 compared to Z + G group. There were only slight changes in the electrolytes concentrations (Na+, K+, Cl-, [Formula: see text] and [Formula: see text]), which were differentially ameliorated by zinc supplementation. The reasons for the various changes recorded were discussed. It was concluded that subchronic oral exposure to glyphosate caused both hepatic and renal functions toxicity in rats, which were ameliorated by zinc supplementation.
