Potencial aterogênico da exposição crônica aos herbicidas glifosato e ácido diclorofenoxiacético (2,4-D) em ratos

Abstract

Introduction: Glyphosate-based herbicides (GBH) and dichlorophenoxyacetic acid (2,4-D) are the most used herbicides in Brazil and worldwide. Both have the ability to form free radicals, which can lead to atherogenesis. Atherosclerosis can lead to life-threatening complications such as myocardial infarction or coronary artery disease, cerebral infarction, and gangrene of the lower limbs. Atherosclerosis is a progressive inflammation of the arteries, and exposure to pesticides has emerged as a risk factor. Objective: The aim of this study was to histologically evaluate and compare the atherogenic potential of chronic oral and inhalation exposure to GBH and 2,4-D in rats, at concentrations similar to those used in crops. Material and methods: 140 adult male albino Wistar rats were used, distributed into 14 groups, 2 control groups, 6 groups exposed to glyphosate and 6 exposed to 2,4-D (n=10/group): CI - Control group inhalation; CO - oral control group; GLI - Group exposed to low concentration of GBH by inhalation; GLO - Group exposed to low concentration of GBH orally; GMI - Group exposed to moderate concentration of GBH by inhalation; GMO - Group exposed to moderate concentration of GBH orally; GHI - Group exposed to high concentration of GBH by inhalation; GHO - Group exposed to high concentration of GBH orally. DLI - Group exposed to low concentration of 2,4-D by inhalation; DLO - Group exposed to low concentration of 2,4-D orally; AMD - Group exposed to moderate concentration of 2,4-D by inhalation; BMD - Group exposed to moderate concentration of 2,4-D orally; DHI - Group exposed to high concentration of 2,4-D by inhalation; DHO - Group exposed to high concentration of 2,4-D orally. The animals were exposed to three concentrations of each herbicide, orally and by inhalation: 3.71 x 10-3 grams of active ingredient per hectare (g.i.a/ha), 6.19 x 10-3 g.i.a/ha and 9.28 x 10-3 g.i.a/ha. Animals were euthanized after 6 months of exposure. The aorta was collected, HE stained for histopathological analysis. Results: Fatty streaks were observed only in animals exposed to herbicides (p< 0.0001), with no difference regarding the route of exposure (oral or inhalation) (p> 0.05). Animals exposed to GBH had twice as many cases with cholesterol streaks as those exposed to 2,4-D (p<0.05). There was no significant difference regarding the thickness of the aorta between exposed and non-exposed to herbicides (p> 0.05). Animals exposed to 2,4-D show greater fractal dimension of nuclei when compared to animals exposed to GBH and those in the control group (p< 0.05). There was no correlation between the measurement of aortic wall thickness and the fractal dimension of the nuclei (r= -0.007, p= 0.933). Conclusion: Both herbicides have atherogenic potential and damage to the arterial wall, but this is greater when exposed to GBH.