Effect of Short-Term Inhalation of The Herbicide 2,4D on Cardiac Remodeling: Morphological Aspects

Abstract Background: Brazil is the worldwide leader in the long-term use of pesticides and herbicides. This compromises the health of handlers by causing harmful neurological, respiratory, and cardiovascular changes. The herbicide 2.4D has been shown to cause cardiac overload with subsequent pathological remodeling. Objective: To analyze the cardiac morphological repercussions on the left ventricle (LV) of mice submitted to nebulization by the herbicide 2.4D. Methods: Fifteen mice were divided into three groups: control group (CG; n = 5) exposed to nebulization with sodium chloride solution; low concentration group (LCG; n = 5) exposed to nebulization of the herbicide 2.4D with 3.71 x 10-3 grams; and high concentration group (HCG; n = 5) exposed to nebulization of the herbicide 2.4D with 9.28 x 10-3 grams for 15 minutes. The fractal dimension analysis was performed through the box-counting method. Later, the ImageJ program was used to calculate the fractal dimension of each group. To evaluate cardiac remodeling, histological slides were prepared and stained with Hematoxylin-Eosin (HE). Fifty areas of cardiomyocytes were analyzed per animal. The comparisons between groups were performed by ANOVA One-Way with Tukey’s posttest (p < 0.05). Results: There was no change in fractal dimension values between the CG = 1.37 ± 0.02, LCG = 1.33 ± 0.04 and the HCG = 1.33 ± 0.07 groups. However, cardiac hypertrophy occurred in the HCG = 303.9 ± 38.80 µm(2) when compared to the CG group = 236.9 ± 61.71 µm(2) (p = 0.034). Conclusion: The herbicide 2.4D used for 72 hours did not promote cardiotoxicity when evaluated by fractal dimension. However, cardiomyocyte hypertrophy was observed in the LV.