Nuclear factor-κB decoy oligodeoxynucleotides attenuates ischemia/reperfusion injury in rat liver graft

AIM: To evaluate the protective effect of NF-κB decoy oligodeoxynucleotides (ODNs) on ischemia/reperfusion (I/R) injury in rat liver graft.METHODS: Orthotopic syngeneic rat liver transplantation was performed with 3 h of cold preservation of liver graft in University of Wisconsin solution containing phosphorothioated double-stranded NF-κB decoy ODNs or scrambled ODNs. NF-κB decoy ODNs or scrambled ODNs were injected intravenously into donor and recipient rats 6 and 1 h before operation,respectively. Recipients were killed 0 to 16 h after liver graft reperfusion. NF-κB activity in the liver graft was analyzed by electrophoretic mobility shift assay (EMSA). Hepatic mRNA expression of TNF-α, IFN-γand intercellular adhesion molecule-1 (ICAM-1) were determined by semiquantitative RT-PCR. Serum levels of TNF-α and IFN-γ were measured by enzyme-linked immunosorbent assays (ELISA). Serum level of alanine transaminase (ALT) was measured using a diagnostic kit. Liver graft myeloperoxidase (MPO) content was assessed.RESULTS: NF-κB activation in liver graft was induced in a time-dependent manner, and NF-κB remained activated for 16 h after graft reperfusion. NF-κB activation in liver graft was significant at 2 to 8 h and slightly decreased at 16 h after graft reperfusion. Administration of NF-κB decoy ODNs significantly suppressed NF-κB activation as well as mRNA expression of TNF-α, IFN-γ and ICAM-1 in the liver graft. The hepatic NF-κB DNA binding activity presented as integral optical density (IOD) value] in the NF-κB decoy ODNs treatment group rat was significantly lower than that of the I/R group rat (2.16±0.78 vs 36.78±6.35 and 3.06±0.84 vs 47.62± 8.71 for IOD value after 4 and 8 h of reperfusion, respectively, P＜0.001).The hepatic mRNA expression level of TNF-α, IFN-y and ICAM-1 presented as percent of β-actin mRNA(%)] in the NF-κBdecoy ODNs treatment group rat was significantly lower than that of the I/R group rat (8.31 ±3.48 vs 46.37±10.65 and 7.46± 3.72 vs 74.82±12.25for hepatic TNF-α mRNA, 5.58±2.16 vs 50.46±9.35 and6.47±2.53 vs 69.72±13.41 for hepatic IFN-γ mRNA, 6.79±2.83 vs 46.23±8.74 and 5.28±2.46 vs 67.44±10.12for hepatic ICAM-1 mRNA expression after 4 and 8 h of reperfusion, respectively, P＜0.001). Administration of NF-κB decoy ODNs almost completely abolished the increase of serum level of TNF-α and IFN-γ induced by hepatic ischemia/reperfusion, the serum level (pg/mL)of TNF-α and IFN-γ in the NF-κB decoy ODNs treatment group rat was significantly lower than that of the I/R group rat (42.7±13.6 vs 176.7±15.8 and 48.4±15.1 vs216.8±17.6 for TNF-α level, 31.5±12.1 vs 102.1±14.5and 40.2±13.5 vs 118.6±16.7 for IFN-γ level after 4 and8 h of reperfusion, respectively, P＜0.001). Liver graft neutrophil recruitment indicated by MPO content and hepatocellular injury indicated by serum ALT level were significantly reduced by NF-κB decoy ODNs, the hepatic MPO content (A655) and serum ALT level (IU/L) in the NF-κB decoy ODNs treatment group rat was significantly lower than that of the I/R group rat (0.17±0.07 vs 1.12±0.25 and 0.46±0.17 vs 1.46±0.32 for hepatic MPO content, 71.7±33.2 vs 286.1±49.6 and 84.3±39.7 vs467.8±62.3 for ALT level after 4 and 8 h of reperfusion,respectively, P＜ 0.001).CONCLUSION: The data suggest that NF-κB decoy ODNs protects against I/R injury in liver graft by suppressing NF-κB activation and subsequent expression of proinflammatory mediators.