Pyrrolidine dithiocarbamate added to University of Wisconsin solution inhibits reperfusion injury after orthotopic liver transplantation in rats

Abstract

This study investigated the effects of pyrrolidine dithiocarbamate (PDTC), a novel NF-kappaB inhibitor, on the expression of multiple inflammatory mediators and on neutrophilic inflammation of the graft in rats following liver transplantation. Orthotopic liver transplantation (OLT) was performed after 24 hr of cold storage using University of Wisconsin (UW) solution that contained various concentrations of PDTC. We determined the time course of NF-kappaB activation and of the expression of multiple inflammatory signals: tumor necrosis factor-alpha (TNF-alpha), cytokine-inducible neutrophil chemoattractant (CINC), and intercellular adhesion molecule-1 (ICAM)-1. Serum alanine aminotransferase (ALT), intrahepatic myeloperoxidase (MPO/WBC ratio, a measure of neutrophil accumulation), and Mac-1 expression (CD11b/CD18, a measure of circulating neutrophil activity) were also evaluated. The results showed that PDTC decreased OLT-induced NF-kappaB activation in a dose-dependent manner (from 20 mmol/L to 60 mmol/L), diminished TNF-alpha, CINC, and ICAM-1 protein levels in the graft, and reduced the OLT-induced increase of serum TNF-alpha level. Pretreatment with PDTC significantly suppressed OLT-induced neutrophilic inflammation of the graft. The PDTC-exposed livers (PDTC, 40 mmol/L), in comparison with the control livers, had a significant reduction of MPO/WBC ratio (7.04+/-0.97 vs 14.07+/-1.31) and Mac-1 expression (181+/-11.3% vs 281+/-13.2%) at 6 hr after reperfusion. Furthermore, PDTC inhibited the increase of serum ALT levels after liver transplantation. In conclusion, PDTC inhibited NF-kappaB activation and the expression of the inflammatory mediators. These effects were associated with improved graft viability through inhibited intrahepatic neutrophilic inflammation. A therapeutic strategy directed at inhibition of NF-kappaB activation within the transplanted liver might be effective in reducing intrahepatic neutrophilic inflammation, and be beneficial to prolonged graft storage.