Chronic aspiration of gastric and duodenal contents and their effects on inflammatory cytokine production in respiratory system of rats.

Gastroesophageal reflux disease (GERD) is defined with clinical symptoms of heart burning and regurgitation. It may be associated with external esophageal symptoms such as chronic cough, asthma, laryngitis, chronic lung disease, sinusitis and pulmonary fibrosis. In the present study, rats with chronic aspiration of gastroduodenal contents were studied for cellular phenotypes and cytokine concentrations in bronchoalveolar lavage and lung tissue. Thirty-six male Albino N-MRI rats were randomly divided into six groups. After anesthesia and tracheal intubation, the animals received either 0.5ml/kg of normal saline (control), gastric juice, pepsin, hydrochloric acid or bile salts by injection into their lungs twice a week for 8 weeks. In sham group nothing was injected. Thereafter, cellular phenotypes and cytokine concentrations of Interleukine (IL)-1α, IL-1β, Transforming Growth Factor (TGF)-β, Tumor Necrosis Factor (TNF)-α, and IL-6 were assessed in bronchoalveolar lavage and lung tissue homogenates. The numbers of epithelial cells, macrophages, neutrophils and lymphocytes in BAL and levels of cytokines IL-1α, IL-6, TNF-α and TGF-β in BAL and lung tissue of test groups were significantly higher than the control group. Aspiration of bile salts caused more cytokine levels and inflammatory cells compared to other reflux components. It can be concluded that GERD with increased cytokines and inflammatory cells in lung could cause or exacerbate asthma and pulmonary fibrosis.