Hydrogen Sulfide Upregulates Cyclooxygenase-2 and Prostaglandin E Metabolite in Sepsis-Evoked Acute Lung Injury via Transient Receptor Potential Vanilloid Type 1 Channel Activation

Hydrogen sulfide (H2S) has been shown to promote transient receptor potential vanilloid type 1 (TRPV1)-mediated neurogenic inflammation in sepsis and its associated multiple organ failure, including acute lung injury (ALI). Accumulating evidence suggests that the cyclooxygenase-2 (COX-2)/PGE(2) pathway plays an important role in augmenting inflammatory immune response in sepsis and respiratory diseases. However, the interactions among H2S, COX-2, and PGE(2) in inciting sepsis-evoked ALI remain unknown. Therefore, the aim of this study was to investigate whether H2S would upregulate COX-2 and work in conjunction with it to instigate ALI in a murine model of polymicrobial sepsis. Polymicrobial sepsis was induced by cecal ligation and puncture (CLP) in male Swiss mice. DL-propargylglycine, an inhibitor of H2S formation, was administrated 1 h before or 1 h after CLP, whereas sodium hydrosulfide, an H2S donor, was given during CLP. Mice were treated with TRPV1 antagonist capsazepine 30 min before CLP, followed by assessment of lung COX-2 and PGE(2) metabolite (PGEM) levels. Additionally, septic mice were administrated with parecoxib, a selective COX-2 inhibitor, 20 min post-CLP and subjected to ALI and survival analysis. H2S augmented COX-2 and PGEM production in sepsis-evoked ALI by a TRPV1 channel-dependent mechanism. COX-2 inhibition with parecoxib attenuated H2S-augmented lung PGEM production, neutrophil infiltration, edema, proinflammatory cytokines, chemokines, and adhesion molecules levels, restored lung histoarchitecture, and protected against CLP-induced lethality. The strong anti-inflammatory and antiseptic actions of selective COX-2 inhibitor may provide a potential therapeutic approach for the management of sepsis and sepsis-associated ALI. The Journal of Immunology, 2011, 187: 4778-4787.