Subchronic exposure to a glyphosate-based herbicide causes dysplasia in the digestive tract of Wistar rats.

Glyphosate-based herbicides (GBH) are the most widely used herbicide for treatment of crops in the world. The digestive tract is one of the first systems exposed to pesticides, and damage to this system can affect the general health of individuals. The aim of this study was to evaluate the effects of subchronic inhalation and oral exposure to GBH on the digestive tract in rats. Six groups of Wistar rats (male and female) were exposed to nebulization with three concentrations of GBH [3.71 × 10-3 grams of active ingredient per hectare (g.a.i./ha), 6.19 × 10-3 g.a.i./ha and 9.28 × 10-3 g.a.i./ha] administered orally or by inhalation for 75 days. Bone marrow cells, smears of the tongue and fragments of the tongue, oesophagus, stomach and intestine were collected for histopathological analysis. Congestion, inflammation, an increase in the number of mast cells and nucleoli-organizing regions were detected in the tongue in the groups exposed to GBH. Females had a higher number of mast cells in the tongue than males. Animals in the groups exposed to higher concentrations of GBH showed dysplasia in the oesophagus and small and large intestine regardless of sex. Gastric changes were not observed. Animals exposed to GBH showed increased micronucleus formation. Our data indicate that GBH causes oral allergies and dysplastic lesions in the oesophagus and small and large intestine and has genotoxic potential.

Oral mucosa changes associated with chronic oral and inhalation exposure to 2,4-dichlorophenoxiacetic acid (2,4-D) in Wistar rats.

The respiratory tract and the oral mucosa are the first areas contaminated by pesticides. The herbicide dichlorophenoxyacetic acid (2,4-D) is a widely used pesticide across the world for both crops and gardens. The aim of this study was to evaluate oral mucosal damage after an experimental simulation of chronic oral and inhalational environmental exposure to 2,4-D formulation. Eighty male Wistar rats were exposed to three distinct concentrations of 2,4-D formulation (low-187.17 mg/m3; medium-313.31 mg/m3; and high-467.93 mg/m3). Oral exposure (through contaminated feed) or inhalation exposure lasted 6 months. Rat tongues were collected for cyto- and histopathology. There was a difference between exposure groups in the intensity of tissue congestion. Most rats exposed to 2,4-D presented mucosal inflammation at both cytology and histology (P < 0.05). Hyperkeratosis only occurred in rats exposed orally at the high concentration. There was an increase in the number of nucleoli-organizing regions in the dorsal epithelium as the 2,4-D concentration increased (P < 0.001). The inhalation route was more associated with increased mitosis figures and nucleoli-organizing region count (P < 0.05). Chronic oral and inhalation exposure to high concentrations of 2,4-D formulation caused an increase in the proliferation rate and thickness of the tongue epithelium and stimulated the inflammatory response in the tissue.