Role Of Hydrogen Sulfide In Acute Lung Injury Induced By Lipopolysaccharide And Its Relationship With Carbon Monoxide

Acute lung injury (ALI), the acute and diffuse injuries to lung tissues caused by various factors, is mainly characterized by inflammatory over-reaction and increased permeability of alveolar-capillary membranes. One of the most common causes of ALI is gram-negative bacterium infection. Lipopolysaccharide (LPS), the main component of the cell wall of gram-negative bacteria, is known to induce severe lung injuries. LPS can directly activate inflammatory cells through binding to its receptors on those cells, which produce a large number of inflammatory mediators, thus causing a cascade of inflammatory reactions. ALI often develops to acute respiratory distress syndrome (ARDS) or even multiple system organ failure. Although remarkable advances have been achieved in the treatment of ARDS, the mortality associated with this syndrome still exceeds 40%, and the exact mechanism of ALI remains incompletely illustrated.Endogenous gaseous transmitters, a unique class of biomaterials in regulating homeostasis, are found to play important roles in a variety of physiological and pathological events. Up to now, three gaseous transmitters have been recognized, namely nitric oxide (NO), carbon monoxide (CO) and hydrogen sulfide (H₂S). Mounting evidence confirmed the important role of NO and CO in ALI. H₂S is the third to be included in the family of endogenous gaseous transmitters, following NO and CO. Researches about physiological functions and pathological effects of H₂S became frequent only recently. It was proved that H₂S participated in the regulation of neural function and vasomotion, as well as the pathogenesis of hypertension, pulmonary artery hypertension and endotoxin shock, etc. However, there were few reports about the role of H₂S in LPS-induced ALI, which was the major...