Effects of Methomyl on DNA, An Experimental Study

Abstract

Methomyl is a carbamate insecticide that is widely used. This study investigates the genotoxic effects of methomyl on mice. Methomyl was given intraperitoneally 10 mice in two doses. Groups: I and III received methomyl as 2.5 mg /kg while groups II and IV received methomyl as 5 mg/kg. Groups I and II were used for the comet and alkaline elution assays, while groups III and IV were used for the micronucleus test. The comet and alkaline elution assays and the micronucleus test are markers for generic damage, while apoptosis is a sequel of this damage. The comet assay and apoptosis were performed on peripheral lymphocytes, while alkaline elution assay was performed on liver and spleen. The micronucleus test was performed on polychromatic erythrocytes (PCEs). Methomyl was found to increase significantly DNA damage in peripheral lymphocytes, liver, spleen and polychromatic erythrocytes. This effect did not improve after 24h except in PCEs although it did not return 10 control levels. Increasing methromyl dose showed different responses in different tissues. Il produced insignificant changes in the PCEs and the spleen, very high significant increase in DNA damage in the peripheral lymphocytes and in the liver and a significant decrease in apoptotic lymphocytes. This may be due to difference in repair efficiency, metabolic activity and / or cell division. So it is recommended to use a combination of tests to assess the genotoxicity of a chemical 10 decrease the incidence of erroneous results. Application of the micronucleus test and the comet assay as monitoring methods for high risk groups to exclude genotoxicity. These tests are rapid, simple and sensitive for measuring and analysing DNA breakage.