Avaliação da neurotoxicidade do herbicida à base de glifosato mediante exposição crônica inalatória e oral em ratos

Abstract

Although industry studies suggest that glyphosate is mildly toxic to non-target species, studies on glyphosate cast doubt on the safety of glyphosate for the health of other species. To evaluate the neurotoxicity of chronic oral and inhalation exposure to the herbicide glyphosate in rats. For the accomplishment of the experiments, 60 male, adult, albino Wistar rats were used, divided into six groups (n=10): CI - Inhalation Control Group, exposed to nebulization with distilled water for 15 minutes, daily; CO - Oral Control Group, feed nebulized with distilled water for 15 minutes; LCI: Low Inhalation Concentration Group, exposed to herbicide spray with 2.99 x 10-3 grams of active ingredient per hectare (g.a.i./ha) for 15 minutes daily; LCO: Low Oral Concentration Group, ration sprayed with the herbicide with 2.99 x 10-3 grams of active ingredient per hectare (g.a.i./ha) for 15 minutes; HCI: High Inhalation Concentration Group, exposed to herbicide spray with 7.48 x 10-3 grams of active ingredient per hectare (g.a.i./ha) for 15 minutes daily; HCO: High Oral Concentration Group, ration sprayed with the herbicide with 7.48 x 10-3 grams of active ingredient per hectare (g.a.i./ha), for 15 minutes. For behavioral evaluation, we used: Open Field Test, Object Recognition Test and Elevated Plus Maze, whose objective was to observe the general state of health, neurological reflexes, sensory abilities and motor function of the animals used. Animals from all groups were euthanized 6 months after the beginning of the experiment. Brain was collected for histological, immunohistochemical and oxidative stress assessment. The animals exposed to GBH showed no change in locomotion or memory impairment. Only those exposed to high oral concentration had a higher level of anxiety. Tissue congestion occurred only in animals exposed to high concentration of GBH. There was a greater thickness of the cerebral cortex and an increase in the expression of the BCL-2 protein in the animals exposed to GBH. Protein carbonylation and maloaldehyde dosages did not differ between exposed and unexposed groups. Under the exposure conditions studied and at product concentrations evaluated, we concluded that the GBH evaluated does not present a neurotoxic effect.