Comparação morfológica pulmonar e do hemograma de ratos expostos cronicamente por via inalatória e oral aos herbicidas glifosato e 2,4-D

Abstract

Brazil is considered the country that consumes the most pesticides in the world, which is a matter of concern for public and environmental health. The forms of exposure to pesticides are varied, among them the most common are oral and inhalation, both of which can cause various harm to health. Among the various pesticides used in Brazil, those leading the sales ranking are glyphosate and 2,4-D. Therefore, the objective of the present study is to evaluate the lung tissue and hematological parameters of rats submitted to inhalational and chronic oral exposure to 2,4-D herbicide and glyphosate. Part of the methodology was carried out in a previous study, which concerns exposure to the 2,4-D herbicide. For glyphosate exposure, 112 male Wistar rats were randomly divided into 14 animals for 8 groups of different concentrations (GC – Control Group; GBC – Low Concentration Group; GMC – Medium Concentration Group and GAC – High Concentration Group), 4 of which were groups exposed by inhalation and 4 groups exposed by oral route. The exposure was carried out for 180 days and after that the animals' blood was collected for making the blood count and euthanasia and collection of lung tissue for analysis of the inflammatory infiltrate and quantification of goblet cells in the airways. Regarding the blood count, it was observed that the animals exposed to glyphosate had high hematocrit values in all rats, however those of the GBC and GMC were significantly reduced in relation to the GC. The same result was observed in the analysis of hemoglobin. Another alteration observed was in relation to fibrinogen values that were normal in the CG and elevated, with statistical difference, in the GAC and in the literature there are indications that fibrinogen levels may be related to cardiovascular diseases. The animals exposed to 2,4-D showed high values of erythrocytes compared to the reference ones, and the animals from the GBC and GAC had significantly higher values than the GC. In lung analysis, no significant increase in goblet cells and inflammatory infiltrate was observed in the groups exposed to herbicides compared to the CG. Therefore, we conclude that both herbicides can trigger hematological changes, however glyphosate has shown to be more toxic to the blood compared to the results found for 2,4-D. In addition, in the period of 6 months, exposure to herbicides did not cause pulmonary alterations. Due to the use of pesticides and other associated substances in agricultural practice, it is suggested to expand research on the effects of combined exposure to these substances on environmental, animal and human health.