Protective effects of hydrogen sulfide inhalation on oxidative stress in rats with cotton smoke inhalation-induced lung injury

The aim of the present study was to investigate the mechanism by which hydrogen sulfide (H2S) inhalation protects against oxidative stress in rats with cotton smoke inhalation-induced lung injury. A total of 24 male Sprague-Dawley rats were separated randomly into four groups, which included the control, H2S, smoke and smoke + H2S groups. A rat model of cotton smoke inhalation-induced lung injury was established following inhalation of 30% oxygen for 6 h. In addition, H2S (80 ppm) was inhaled by the rats in the H2S and smoke + H2S groups for 6 h following smoke or sham-smoke inhalation. Enzyme-linked immunosorbent assays were performed to measure various indices in the rat lung homogenate, while the levels of nuclear factor (NF)-Bp65 in the lung tissue of the rats were determined and semiquantitatively analyzed using immunohistochemistry. In addition, quantitative fluorescence polymerase chain reaction was employed to detect the mRNA expression of inducible nitric oxide synthase (iNOS) in the rat lung tissue. The concentrations of malondialdehyde (MDA), nitric oxide (NO), inducible iNOS and NF-Bp65, as well as the sum-integrated optical density of NF-Bp65 and the relative mRNA expression of iNOS, in the rat lung tissue from the smoke + H2S group were significantly lower when compared with the smoke group. The concentrations of MDA, NO, iNOS and NF-Bp65 in the H2S group were comparable to that of the control group. Therefore, inhalation of 80 ppm H2S may reduce iNOS mRNA transcription and the production of iNOS and NO in rats by inhibiting NF-Bp65 activation, subsequently decreasing oxidative stress and cotton smoke inhalation-induced lung injury.