Avaliação dos efeitos da associação dos herbicidas 2,4 – D e picloram sobre parâmetros de toxicidade em Drosophila melanogaster

Abstract

Pesticides are substances widely used in agriculture and are often responsible for environmental problems, human and animal intoxication. 2,4-D is a herbicide that exhibits moderate persistence in soils and the potential for contamination of groundwater. Picloram is the active ingredient of growth regulating herbicides that act similarly to 2,4-D. The fruit fly, D. melanogaster, has proved to be a tool to evaluate the impact of environmental stresses, since it has structures that perform functions equivalent to those of mammals, contributing as a model for studies of development, behavior and human diseases. Thus, exposure of D. melanogaster and mammalian cells to pesticides may result in similar biochemistry alterations, indicating that the fruit fly can be considered a model for the study of pesticide toxicity. Therefore, the present work aims to evaluate the toxicity of the herbicides 2,4 - D and Picloram in association in the fruit fly, D. melanogaster. It was used a commercial mixture of 2,4 - D and picloram with concentrations of 114.76 g / L picloram and 447.22 g / L 2,4 - D. For the study of development and survival, curves with different concentrations of herbicides parallel to a control group were set up without addition of herbicides. Female and male flies were analyzed separately. In addition to survival, the locomotor behavior, acetylcholinesterase activity, production of reactive oxygen species, levels of total and non-protein thiols, and total antioxidant activity of the compound were analyzed. The results obtained demonstrate that an exposure of eggs and larvae of D. melanogaster to the herbicide under study does not affect the development significantly. Exposure of adult subjects caused progressive mortality in a dose-dependent manner. Regarding the behavioral test, co-exposure to herbicides led to a significant reduction in locomotion when compared to the control group and, as in the mortality analysis, male subjects were more affected by the toxic effects of the herbicides under study. Regarding the acetylcholinesterase activity, the results show that the association of the herbicides caused significant increase in enzyme activity in males of D. melanogaster. Considering the effects on thiol levels, while there was a decrease in non-protein thiol levels with increased herbicide concentration, total thiol levels were not uniformly affected. The production of reactive oxygen species was decreased in the heads and increased in the bodies of D. melanogaster. For the total antioxidant activity, it was observed that the herbicide has antioxidant activity in all dilutions tested with a total antioxidant activity of 130.7% for the dilution 1/10. From the analysis of the results, it is possible to conclude that the association of the herbicides 2,4-D and picloram cause remarkable toxic effects in D. melanogaster.