Effect of hydrogen inhalation on IL-40 and SIgA in a Rat Model of Pulmonary Mucosal Immunity

Background Recently, some researchers have reported that PIgR expression is down-regulated in Chronic Obstructive Pulmonary Disease (COPD) and SIgA deficiency correlates with severity of airflow obstruction. What’ s more, some studies have demonstrated that 2 percent of hydrogen or hydrogen water is effective in treating and preventing various diseases. Objectives The aim of this study was to observe the effect of hydrogen on the expression of SIgA, PIgR, IL-4, IL-5, TGF-β1 and IL-40 in lung tissue of COPD rats, to study the relationship between lung pathology parameter and SIgA, PIgR, therefore we can understand the effect of hydrogen on the development of COPD by changing SIgA expression of airway mucosal in COPD rats. Methods A rat model of COPD was established by cigarette smoke exposure, and different concentrations of hydrogen were inhaled as intervention measures. After 4 months of cigarette smoke exposure, pathologic changes and airway wall remodeling of the lung were assessed by optical microscope. The protein expressions of SIgA, PIgR, IL-4, IL-5, TGF-β1 as well as IL-40 in the lung tissues were observed by immunohistochemistry or Western blot. The correlation between lung pathology parameter and the expression of SIgA, PIgR was analyzed. The correlation between SIgA and the expression of IL-4, IL-5, TGF-β1 and IL-40 was analyzed. Results The results showed that hydrogen inhalation significantly ameliorated lung pathology and airway wall remodeling, increased the protein expression of SIgA, PIgR, IL-4, IL-5, and IL-40, and reduced the protein expression of TGF-β1. Conclusions Inhalation of 22% and 41.6% hydrogen showed a better effect than inhalation of 2% hydrogen. Hydrogen inhalation can significantly improve the expression of SIgA on the mucosal surface of COPD rats, which may be one of the mechanisms which hydrogen works on COPD pathogenesis.