Cholecystokinin protects mouse liver against ischemia and reperfusion injury

BackgroundCholecystokinin (CCK), as a gastrointestinal hormone, has an important protective role against sepsis or LPS-induced endotoxic shock. We aim to address the role of CCK in hepatic ischemia followed by reperfusion (I/R) injury.Materials and methodsA murine model of 60 min partial hepatic ischemia followed by 6 h of reperfusion was used in this study. CCK and CCKAR Levels in blood and liver were detected at 3 h, 6 h, 12 h and 24 h after reperfusion. Then the mice were treated with CCK or proglumide, a nonspecific CCK-receptor (CCK-R) antagonist. Mice were randomly divided into four groups as follows: (1) sham group, in which mice underwent sham operation and received saline; (2) I/R group, in which mice were subjected to hepatic I/R and received saline; (3) CCK group, in which mice were subjected to hepatic I/R and treated with CCK (400 μg/kg); (4) proglumide group (Pro), in which mice underwent hepatic I/R and treated with proglumide (3 mg/kg); CCK and proglumide were administrated via tail vein at the moment of reperfusion. Serum AST (sAST) and serum ALT (sALT) were determined with a biochemical assay and histological analysis were performed with hematoxylin-eosin (H&E). Cytokines (IL-1β, IL-6, IL-10, TNF-α) expressions in blood were determined with enzyme-linked immunosorbent assay (ELISA). The MPO (myeloperoxidase) assay were used to measure neutrophils' infiltration into the liver. The apoptotic index (TUNEL-positive cell number / total liver cell number × 100%) was calculated to assess hepatocelluar apoptosis. Finally, activation of NF-κB and phosphor-p38 expression in liver homogenates were analyzed with Western Blot (WB).ResultsOur findings showed that 1) CCK and CCK-AR were upregulated in our experimental model over time; 2) Treatment with CCK decreased sAST/sALT levels, inflammatory hepatic injury, neutrophil influx and hepatocelluar apoptosis, while proglumide aggravated hepatic injury.ConclusionThese findings support our hypothesis and suggest that CCK played a positive role in the ongoing inflammatory process leading to liver I/R injury.