The effect of CSE gene deletion in caerulein-induced acute pancreatitis in the mouse

Hydrogen sulfide (H₂S) has been reported to be involved in the signaling of the inflammatory response; however, there are differing views as to whether it is pro- or anti-inflammatory. In this study, we sought to determine whether endogenously synthesized H₂S via cystathionine-γ-lyase (CSE) plays a pro- or anti-inflammatory role in caerulein-induced pancreatitis. To investigate this, we used mice genetically deficient in CSE to elucidate the function of CSE in caerulein-induced acute pancreatitis. We compared the inflammatory response and tissue damage of wild-type (WT) and CSE knockout (KO) mice following 10 hourly administrations of 50 μg/kg caerulein or saline control. From this, we found that the CSE KO mice showed significantly less local pancreatic damage as well as acute pancreatitis-associated lung injury compared with the WT mice. There were also lower levels of pancreatic eicosanoid and cytokines, as well as reduced acinar cell NF-κB activation in the CSE KO mice compared with WT mice. Additionally, in WT mice, there was a greater level of pancreatic CSE expression and sulfide-synthesizing activity in caeruleininduced pancreatitis compared with the saline control. When comparing the two saline-treated control groups, we noted that the CSE KO mice showed significantly less pancreatic H₂S-synthesizing activity relative to the WT mice. These results indicate that endogenous H₂S generated by CSE plays a key proinflammatory role via NF-κB activation in caeruleininduced pancreatitis, and its genetic deletion affords significant protection against acute pancreatitis and associated lung injury.