Studies on the ameliorative effect of vitamin E on paraquat toxicity in rats

Abstract

The present study entitled ‘Studies on the ameliorative effect of vitamin E on paraquat toxicity in rats’ was undertaken by administering the animals with paraquat dichloride and vitamin E for a period of 28 days. The weekly body weights, clinical signs, haematology and biochemical parameters were analysed. Of the twelve animals in each group, six animals were sacrificed at the end of second week and remaining at the end of forth week. The gross pathology and histopathology of various organs were studied. The oxidative damage of the lungs and kidneys was assessed by the estimation of lipid peroxides and reduced glutathione. None of the animals in the experimental groups revealed any clinical signs of toxicity except for one rat each from paraquat alone treated group and paraquat plus vitamin E treated group which became weak towards the end of experiment. Although, all the groups showed a gradual increase in body weight, those animals treated with paraquat alone and those with paraquat and vitamin E showed a reduced weight gain when compared with the control group. The AST, ALT, ALP and creatinine values showed a significant increase in treatment groups compared to the control. In vitamin E treated group, a slight decrease was noticed in these biochemical parameters. Hb and PCV values showed a significant decrease and the total leukocyte count showed a significant increase in treatment groups when compared to control group. There was no variation in the erythrocyte sedimentation rate and differential leukocyte count. In vitamin E treated group, a slight increase in Hb and PCV values were noticed. There was an increase in the lipid peroxides and concurrent reduction in the glutathione in the lung and kidney homogenate which indicated oxidative damage. Gross lesions were almost similar in both treatment groups. The congestive changes were noticed in lungs, kidneys and liver. The histopathological changes noticed in paraquat alone treated group were congestion, haemorrhage, focal areas of necrosis with proliferation of fibroblasts in the lungs, thickening of the interalveolar septa. The bronchi revealed desquamation of proliferated epithelium. Degenerative changes in the renal tubules, focal necrotic changes in the liver and varying degrees of degenerative changes in the heart, stomach, intestine and brain were the other lesions noticed. These lesions became more intensified in animals treated for four weeks. In vitamin E treated group, a slight reduction in the intensity of lesion was noticed. The bronchial epithelium was intact. Mild proliferation of fibroblasts and congestive changes were also noticed in the lungs. Focal necrotic changes were noticed in the kidneys and liver. Mild degenerative changes were noticed in the heart and intestine. The study revealed that the vitamin E is not completely suitable for management of the renal and pulmonary disorders in subacute paraquat toxicity in rats.