Histone deacetylase regulates trypsin activation, inflammation, and tissue damage in acute pancreatitis in mice.

The onset of acute pancreatitis (AP) is characterized by early protease activation followed by inflammation and organ damage, but the mechanisms are poorly understood. We hypothesized that histone deacetylase (HDAC) inhibition might exert protective effects on AP and investigated the role of HDAC in trypsin activation, inflammation, and tissue damage in severe AP. Male C57Bl/6 mice were treated i.p. with the HDAC inhibitor trichostatin A (2 mg/kg) prior to retrograde infusion of taurocholic acid (5 %) into the pancreatic duct. Serum levels of amylase and interleukin (IL)-6, pancreatic levels of macrophage inflammatory protein-2 (MIP-2) as well as tissue morphology and myeloperoxidase activity in the pancreas and lung were determined 24 h after taurocholate challenge. Trypsin activation was analyzed in isolated acinar cells. Quantitative RT-PCR was used to examine the expression of pro-inflammatory mediators in the pancreas. Pretreatment with trichostatin A decreased amylase levels by 70 % and protected against tissue injury in the pancreas. Moreover, HDAC inhibition reduced systemic IL-6 by more than 95 % and pulmonary myeloperoxidase activity by 75 %. Notably, inhibition of HDAC abolished taurocholate-induced gene expression of cyclooxygenase-2, MIP-2, monocyte chemotactic protein-1, IL-6, and IL-1β in the pancreas. In addition, HDAC inhibition reduced cerulein-induced trypsinogen activation in isolated acinar cells. Our findings show that HDAC regulates trypsin activation, inflammation, and tissue damage in AP. Thus, targeting HDAC could serve as novel therapeutic approach in the management of severe AP.