Hydrogen Sulfide Exerts Anti-oxidative and Anti-inflammatory Effects in Acute Lung Injury

Acute lung injury (ALI) caused by septic stimuli is still a major problem in critical care patients. We have shown previously that hydrogen sulfide (H₂S) mediates anti-inflammatory and lung protective effects. In the present study, we aimed to investigate the underlying mechanisms. C57BL/6N mice were instilled with lipopolysaccharide (LPS) intranasally in the absence or presence of inhaled H₂S for 6 h. LPS instillation led to alveolar wall thickening, an elevated ALI score, increased neutrophil transmigration, and elevated interleukin-1β cytokine release into the bronchoalveolar lavage fluid. In contrast, H₂S inhalation prevented lung injury and inflammation despite LPS treatment. Moreover, H₂S inhalation significantly inhibited protein expression of cystathionine-β-synthetase, heat shock protein 70, phosphorylated p38 MAP kinase, NADPH oxidase 2, and the formation of reactive oxygen species (ROS) in LPS-challenged animals. In conclusion, H₂S prevents LPS-induced ALI by inhibition of pro-inflammatory and oxidative responses via the concerted attenuation of stress protein, MAP kinase, and ROS signaling pathways.