Histopathological effects of pesticide-cholopyrifos on kidney in albino rats

Abstract

AIM: Pathological lesions have been widely used as biomarkers for health evaluation of organism exposed to pollutants and can be used as warning symptoms for organism health. There are few reports regarding morphological changes in kidney following pesticide Chlorpyrifos exposure which has prompted us to undertake this study. MATERIALS AND METHODOLOGY: The present study was conducted on 45 inbred adult Wistar albino rats of either sex, weighting 145 165 gms. These animals were randomly divided into 3 groups A, B, C. Oral Chlorpyrifos was given to the experimental groups B and C in dose of 5 mg/kg body weight and 10 mg/kg body weight respectively. Group A served as control and was left as such. The animals were observed for clinical signs of toxicity and behavioral changes throughout the experimental period. Body weight was recorded at zero day and then at 2 weekly interval for 8 weeks. 3 animals from each group were sacrificed after 1 week, 2nd week, 4th week, 6th week and 8th week of initiation of experiment to see the morphological changes in the kidney architecture. RESULTS: Gross The animals in group A were active, quick to respond and food intake was normal throughout the experimental period where as the animals of groups B & C showed decreased physical activity, dullness, depression, Piloerection, shivering salivation and lacrimation with more severity in Group C. Body Weight Decrease in weight gain was observed in both experimental groups (B & C) as compared to control group A. A statistically significant decrease in weight gain was observed in Group C after 6th and 8th week of Chlorpyrifos treatment. Macroscopic Changes Grossly the kidneys of rats in control group showed no significant changes. The kidneys of rats in Group B showed no change in colour and consistency after 1st, 2nd, and 4th weeks of treatment with Chlorpyrifos. However after 6th week there was congestion, thickening and adherence of capsule at some places. With increasing dose and duration of treatment with Chlorpyrifos i. e after 8th week the kidneys were small in size, shrunken and had irregular contour. In Group C upto 1st week of treatment with Chlorpyrifos the kidneys were normal in gross appearance but after 2nd, 4th and 6th weeks the kidneys were grossly congested and friable to touch and the capsule was thickened. After 8 weeks of exposure the kidneys were small in size, shrunken and had irregular contour with thickened outer capsule. Naked eye observations of coronal section of kidney Group A showed clear demarcation of outer cortex and inner medulla. Group B showed no visible change after 1st and 2nd weeks of treatment. After 4th and 6th week there was visible haemorrhage at corticomedullary junction ranging from focal to completely obscuring of corticomedullary junction. After 8th week there was no demarcation between cortex and medulla and whole of medulla was congested. Group C (10 mg/kg b wt) upto 1st week there was no significant visible change in coronal section of kidneys. After 2nd and 4th weeks there was visible haemorrhage at corticomedullary junction. After 6 weeks of treatment whole of the medulla was congested and after 8weeks there was no demarcation between cortex and medulla, whole of the coronal section of the kidneys showed dark reddish brown colour due to haemorrhage. CONCLUSION: The present study showed that significant morphological changes were caused in the kidneys of rats administered with Chlorpyrifos. These changes were markedly different from the control rats. Hence this study brought into light the renal toxicity induced by Chlorpyrifos which was found to be significant at high dose level.