Protective effect of hydrogen sulfide in a murine model of acute lung injury induced by combined burn and smoke inhalation

Acute lung injury results in a severe inflammatory response, which leads to priming and activation of leucocytes, release of reactive oxygen and reactive nitrogen species, destruction of pulmonary endothelium, extravasation of protein-rich fluid into the interstitium and formation of oedema. Recently, H₂S (hydrogen sulfide) has been shown to decrease the synthesis of pro-inflammatory cytokines, reduce leucocyte adherence to the endothelium and subsequent diapedesis of these cells from the microvasculature in in vivo studies, and to protect cells in culture from oxidative injury. In the present study, we hypothesized that a parenteral formulation of H₂S would reduce the lung injury induced by burn and smoke inhalation in a novel murine model. H₂S post-treatment significantly decreased mortality and increased median survival in mice. H₂S also inhibited IL (interleukin)-1β levels and significantly increased the concentration of the anti-inflammatory cytokine IL-10 in lung tissue. Additionally, H₂S administration attenuated protein oxidation following injury and improved the histological condition of the lung. In conclusion, these results suggest that H₂S exerts protective effects in acute lung injury, at least in part through the activation of anti-inflammatory and antioxidant pathways.