Goma do cajueiro (Anacardium occidentale L.) reduz a inflamação e disfunção pulmonar secundárias ao refluxo gastroesofágico em camundongos

Abstract

Gastroesophageal Reflux Disease (GERD) is a chronic disease capable of causing extraesophageal symptoms, affecting the patient's life. In addition to the typical reflux symptoms, it can lead to extraesophageal manifestations such as chronic cough, laryngitis, pharyngitis, among others. The use of standard therapy to treat reflux does not prevent the pulmonary impairment caused by reflux and therefore new therapeutic approaches are needed to improve these extraesophageal symptoms. Cashew gum (CG), which has already been used in an experimental reflux model in mice and in human esophageal biopsies with GERD, could be an alternative for treating these extraesophageal manifestations. With this in mind, the present study sought to evaluate the effect of CG on inflammation and pulmonary dysfunction secondary to gastroesophageal reflux (GER) using a surgical model consisting of pyloric substenosis and complete ligation of the gastric fundus in male Swiss mice (30-35 g). The experimental groups were: I - Sham control group (sham operated); group II - 28-day GER and group III - 28-day GER + 10% CG (via gavage). On the 28th day after surgery, spirometry was performed on the animals, after which they were euthanized to remove the esophagus for analysis of wet weight and myeloperoxidase (MPO), and the lungs in order to measure the wet weight/dry weight ratio, MPO activity and histopathological analysis. After 28 days of surgery, there was an increase in esophageal wet weight and MPO activity (p < 0.05) in the animals induced with GER, while treatment with 10% CG reversed this inflammatory process, showing reproducibility of the surgical model and improvement in the inflammatory response due to treatment with CG. In the lungs, there was an increase in the wet/dry weight ratio in the animals induced with GER and in MPO activity, showing pulmonary edema and participation in the inflammatory response when compared to the Sham group. In contrast, the animals treated with 10% CG had a significant reduction in wet/dry weight and MPO values in the lung compared to the operated group (p < 0.05). Histologically, there were changes in the inflammatory response (alveolitis) in the animals with GER compared to the Sham group, while there was a reduction in alveolitis in the animals treated with 10% CG compared to the 28-day GER group (p < 0.05). However, the histopathological analysis of fibrosis did not show a significant reduction in the group treated with 10% CG. Functional data showed a reduction in the respiratory capacity of the animals with GER compared to the Sham group, while the animals treated with 10% CG had an improvement in respiratory function (p < 0.05). In addition, 10% CG had no effect on inhibiting pepsin activity in vitro. This shows that the use of gum reduced lung inflammation and improved lung functional parameters in mice with experimental GER.