Protective effects of gastrin-releasing peptide receptor antagonist RC-3095 in an animal model of hepatic ischemia/reperfusion injury.

Abstract

We aimed to evaluate effects of RC-3095 on mice with hepatic ischemia followed by reperfusion (I/R) injury and further explore the possible underlying mechanism. Mice were subjected to partial hepatic ischemia for 60min followed by different durations of reperfusion. Levels of gastrin-releasing peptide (GRP) and GRP receptor (GRPR) in the blood and liver were detected by enzyme-linked immunosorbent assay (ELISA) or western blotting (WB) after 3, 6, 12, or 24h of reperfusion. RC-3095 or normal saline (control) was given i.p. at the time of reperfusion. Expressions of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, and IL-10 in blood and liver samples were examined with ELISA. Neutrophil influx into the liver was assessed by flow cytometry and myeloperoxidase assay. Hematoxylin-eosin staining of the liver and terminal deoxynucleotidyl transferase mediated dUTP-biotin nick end labeling assay were used to determine hepatic injury and hepatocellular necrosis. Activation of nuclear factor (NF)-κB and p38/extracellular regulated protein kinase (ERK) mitogen activated protein kinase (MAPK) was investigated with WB. The expression of GRP was upregulated within 3h after reperfusion and remained elevated for up to 24h in the liver, whereas GRPR was also upregulated after 3 or 6h of reperfusion, but returned to baseline levels within 24h. RC-3095 significantly reduced the inflammatory hepatic injury, liver neutrophil accumulation, and hepatocellular apoptosis, probably by inhibiting activation of NF-κB or p38/ERK MAPK. These findings supported that GRP-GRPR played an important role in hepatic I/R injury, and RC-3095 ameliorated liver damage by suppressing the inflammatory response and hepatocellular necrosis.