Role of hydrogen sulfide in cecal ligation and puncture-induced sepsis in the mouse

Endogenous hydrogen sulfide (H2S) is naturally synthesized in various types of mammalian cells from L-cysteine in a reaction catalyzed by two enzymes, cystathionine-gamma-lyase (CSE) and/or cystathionine-beta-synthase. The latest studies have implied that H2S functions as a vasodilator and neurotransmitter. However, so far there is little information about the role played by H2S in systemic inflammation such as sepsis. Thus the aim of this study was to investigate the potential role of endogenous H2S in cecal ligation and puncture (CLP)-induced sepsis. Male Swiss mice were subjected to CLP-induced sepsis and treated with saline (ip), DL-propargylglycine (PAG, 50 mg/kg ip), a CSE inhibitor, or sodium hydrosulfide (NaHS; 10 mg/kg ip). PAG was administered either 1 h before or 1 h after the induction of sepsis, whereas NaHS was given at the same time of CLP. CLP-induced sepsis significantly increased the plasma H2S level and the liver H2S synthesis 8 h after CLP compared with sham operation. Induction of sepsis also resulted in a significant upregulation of CSE mRNA in liver. On the other hand, prophylactic as well as therapeutic administration of PAG significantly reduced sepsis-associated systemic inflammation, as evidenced by myeloperoxidase activity and histological changes in lung and liver, and attenuated the mortality of CLP-induced sepsis. Injection of NaHS significantly aggravated sepsis-associated systemic inflammation. Therefore, the effect of inhibition of H2S formation and administration of NaHS suggests that H2S plays a proinflammatory role in regulating the severity of sepsis and associated organ injury.