Significant Expression of Interleukin 15 in Rat Experimental Severe Acute Pancreatitis

Purpose: In severe acute pancreatitis (SAP), multiple organ dysfunction syndrome is a contributor to high mortality. We recently demonstrated that the serum interleukin (IL)-15 level is a predictor of the complications and mortality in clinical SAP. The aim was to investigate the role of IL-15 in experimental SAP. Materials and Methods: SAP was induced by retrograde injection of 3 and 20% sodium deoxycholate (DCA) into biliopancreatic ducts in rats (DCA pancreatitis). Expressions of IL-15 were evaluated by Western blotting and immunohistochemical staining. Recombinant IL-15 protein was administered intraperitoneally, and the effects were investigated. Results: Western blotting revealed the expressions of IL-15 in the pancreas, liver, lung and intestine in 3% DCA pancreatitis. Immunohistochemical staining showed the expression of IL-15 in the cytoplasm of each organ. In 3% DCA pancreatitis, administration of recombinant IL-15 protein attenuated the elevation of serum alanine aminotransferase (ALT) levels and improved the morphological change of the lung 18 h after the induction of SAP. Moreover, in 20% DCA pancreatitis, IL-15 improved the elevation of serum amylase and ALT levels 6 h after the induction. Conclusions: These results suggest that IL-15 is related to organ dysfunction during SAP, and that IL-15 functions as a protective factor against the organ injuries.