Avaliação da toxicidade ao trato digestório e glândulas anexas mediante a exposição subcrônica inalatória e oral do agrotóxico glifosato em ratos

Abstract

Introduction: Although studies carried out by the industry suggest that glyphosate is not very toxic for non-target species, but recent research has put into question the safety of the compound for the health of other species. Objective: To evaluate the histological, cytological and morphometric changes of the digestive system and attached glands, caused by subchronic oral and inhalation exposure to the herbicide glyphosate in rats. Material and methods: For the experiments, 88 adult male and female albino Wistar rats were used, distributed in nine groups with ten animals each (5 males and 5 females), with the exception of the positive control group, formed by 8 males that received 50 mg / kg after 24h of experiment.: Inhalation Control Group, exposed to nebulization with chloride solution sodium (NaCl) for approximately 15 minutes, daily; Oral Control Group, received nebulized feed with NaCl solution for approximately 15 minutes; Low Concentration Inhalation Group, exposed to nebulization to the herbicide with 3.71 x 10-3 grams of active ingredient per hectare (g.i.a / ha), for 15 minutes, daily; Low Oral Concentration Group, received nebulized feed with the herbicide with 3.71 x 10-3 grams of active ingredient per hectare (g.i.a / ha) for approximately 15 minutes; Medium Concentration Inhalation Group, exposed to nebulization to the herbicide with 6.19 x 10-3 grams of active ingredient per hectare (g.i.a / ha), for 15 minutes, daily; Medium Oral Concentration Group, received nebulized feed with the herbicide with 6.19 x 10-3 grams of active ingredient per hectare (g.i.a / ha), for approximately 15 minutes; High Concentration Inhalation Group, exposed to nebulization to the herbicide with 9.28 x 10-3 grams of active ingredient per hectare (g.i.a / ha), for 15 minutes, daily; High Oral Concentration Group, received food nebulized with the herbicide with 9.28 x 10-3 grams of active ingredient per hectare (g.i.a / ha), for approximately 15 minutes. Blood was collected for liver and kidney function tests and fragments of the mouth, liver, kidney, spleen, pancreas and esophagus, stomach and small and large intestine for histopathological analysis. Femoral bone marrow cells were collected for the micronucleus test. Results: There was a predominance of karyomegaly in females, in the oral cavity. In the tongue there was congestion, inflammation, an increase in the number of mast cells and the number of nucleolus organizing regions in the groups exposed to glyphosate, regardless of the sex of the animals (p <0.05). All animals exposed to high concentration showed dysplasia in the esophagus. In the analysis of the large intestine, 80% of the animals in the group exposed to medium inhalation concentration and 88% of the animals in the group exposed to medium oral concentration and in the group exposed to high inhalation concentration, presented mild mucosal dysplasia, while moderate dysplasia was observed in 22% of the animals in the group exposed to high inhalation concentration and in 100% of the group exposed to high oral concentration. In the small intestine, mild dysplasia was observed in 50% of the animals in the group exposed to medium inhalation concentration, 90% of the animals in the group exposed to high inhalation concentration and in 100% of animals in the groups exposed to medium and high oral concentration. There was a greater increase in micronuclei in females exposed to low oral concentration and males exposed to high inhalation concentration. Females in the group exposed to high oral concentration had the highest concentrations of AST, ALT, creatinine and urea (p <0.05). Liver steatosis was observed in all animals exposed to medium and high glyphosate concentration (p <0.05). All those exposed to glyphosate showed tubular changes. Tubular necrosis was more prevalent in animals in the group exposed to high oral concentration. The count of NORs (nucleus organizing regions), in the liver and kidney, was higher in animals exposed to high concentrations of glyphosate (p <0.05). No changes were found in the stomach, spleen and pancreas in any of the groups studied. Conclusion: Glyphosate stimulates an inflammatory process in the digestive tract, can cause oral allergies (mainly in females), dysplastic lesions in the esophagus and small and large intestine and has genotoxic potential, characterized by an increase in micronuclei in exposed animals. In general, the oral route causes more changes in the digestive tract than the inhalation route. Exposure to high concentrations of glyphosate, mainly orally, causes greater liver and kidney damage, especially to females.