Prevention of TLR9 Pathway in Warm Ischemia in Porcine Donor Liver after Cardiac Death

Abstract

Objective: To investigate effect of warm ischemia after cardiac death on activation of TLR9 pathway in porcine liver.

Methods: Donor of cardiac death (DCD) model was established with Duroc, Landrace, Large White crossbred pigs. Liver tissues from the animals were harvested at 0, 5, 10, 15, 25 and 30 minutes after warm ischemia for analysis of expression of TLR9, IRF7, IFN-β, and TNF-α at mRNA and protein levels by real-time PCR and western blot, respectively, and for assessment of NF-κB/DNA binding activity by western blot detection of p65 protein.

Results: Ischemia induced TLR9, IRF7, IFN-β, and TNF-α expression at both mRNA and protein levels in an ischemic time dependent manner. Among them, expression of TNF-α and IFN- β was induced later than TLR9 and IRF7 did. Ischemia also enhanced NF-κB binding to DNA in the DCD liver tissue. Pretreatment with iCpG specifically blocked activation of TLR9 pathway triggered by ischemia in liver and protected the animals from ischemia-caused liver tissue damage.

Conclusion: Warm ischemia activates TLR9 pathways in the porcine liver tissue. Blocking TLR9 pathway could offer protection from ischemia-caused liver tissue in DCD liver transplantation.

Keywords: Ischemia; Liver transplant; Signal transduction; Toll-like receptor.