Animal study for airway inflammation triggered by gastroesophageal reflux

Background Gastroesophageal reflux disease with extra-esophageal symptoms, especially those with respiratory distress was attracting more and more attention. The related mechanisms were still in controversy. The purpose of the work was to explore airway inflammation triggered by gastroesophageal reflux. Methods Sixteen Sprague-Dawley rats were used as study group and 9 as control. In the study group, a plastic extender with a trumpet-shaped distal end was inserted into the lower esophagus to dilate the cardia, the pylorus was ligated. One ml of 0.1 mol/L hydrochloric acid was injected into the stomach. While a simple laparotomy was performed for control animals. All animals from two groups were sacrificed 24 hours after operation. Then tracheotomy was carried and the bronchoalveolar lavage fluid was collected in all animals. Cells in the fluid were counted and levels of interleukin (IL)-5, -6, -8 in it were measured. Results Compared with control group, the study group presented a neutrophil pattern of airway inflammation and an elevated concentration of IL-5, -6, -8 with no significant difference regarding eosinophil count. Conclusion The gastroesophageal reflux-triggered airway inflammation is characterized by a neutrophilic airway inflammation which differed from that caused by asthma, and enhanced levels of IL-5, -6 and -8, which are similar to that caused by asthma.