Hydrogen gas inhalation protects against cigarette smoke-induced COPD development in mice

Methods: A COPD mouse model was established in male C57BL mice by cigarette smoke (CS) exposure. The H2 intervention was administered by atomisation inhalation. Lung functions were assessed by using Buxco lung function measurement system. The inflammatory cells were counted and the levels of IL-6 and KC in BALF were assayed with ELISA. The lung tissue was subjected to H&E or PAS or Masson's trichrome stain. Furthermore, 16HBE cells were used to evaluate the effects of H2 on signaling change caused by hydrogen peroxide (H2O2). H2O2 was used to treat 16HBE cells with or without H2 pretreatment. The IL-6 and IL-8 levels in cell culture medium were measured. The levels of phosphorylated ERK1/2 and nucleic NF-κB in lungs and 16HBE cells were determined.

Results: H2 ameliorated CS-induced lung function decline, emphysema, inflammatory cell infiltration, small-airway remodelling, goblet-cell hyperplasia in tracheal epithelium and activated ERK1/2 and NF-κB in mouse lung. In 16HBE airway cells, H2O2 increased IL-6 and IL-8 secretion in conjunction with ERK1/2 and NF-κB activation. These changes were reduced by H2 treatment. Conclusions: These findings demonstrated that H2 inhalation could inhibit CS-induced COPD development in mice, which is associated with reduced ERK1/2 and NF-κB-dependent inflammatory responses.