Hepatotoxicity and elastogenicity of dichlorvos at high doses in male Wistar rats

Abstract

Introduction: Dichlorvos (2, 2-dichlorovinyI dimethyl phosphate (DDVP) is widely used in Nigeria for the preservation of stored grains, especially dry beans. Residues of this organophosphate pesticide may therefore inadvertently be present in such products. The present study investigates the hepatotoxic and elastogenic effect of high doses of DDVP in rats as a mimic to its indiscriminate use on store products. Methods: Male rats (100-150 g) were randomly divided into six groups of five each. Treatments (p.o) were as follows: Group 1-distilled water; Group 2 (control)-corn oil; Groups (3-5)-varying doses of DDVP (5-20 mg/kg b.w) and Group 6-(2.5 mg/kg) sodium arsenite. After 28 days, indices of hepatotoxicity [serum activities of gamma-glutamyl transferase (ϒGT), alkaline phosphatase (ALP), alanine and aspartate aminotransferase (ALT and AST) and elastogenicity [relative number of micronucleatcd polychromatic erythrocytes (mPCEs)] were determined. Results: DDVP at all the tested doses induced significant (p < 0.05) increase in activities of yGT, ALP, ALT and AST. It also significantly (p < 0.05) induced mPCEs formed in the bone marrow as compared with the control. The level of induction was dose dependent in both eases. In addition, there was significantly (p < 0.05) higher number of hepatic cells in the cell/mm2 assay for the group treated with DDVP. Histopathological analysis of liver samples from the treated groups revealed lesions corroborating the biochemical indices above. Conclusion: Findings from this study suggest that DDVP has elastogenic and hepatotoxic effects in rats. There is therefore a need for strict regulatory control and monitoring of the use and residues of DDVP in stored products.