Effect of interferon regulatory factor-1 on murine liver ischemia-reperfusion injury via P38 MAPK signaling pathway

Abstract

Objective To explore the effect of interferon regulatory factor-1(IRF-1)on murine liver ischemia-reperfusion injury (IRI) via P38 MAPK signaling pathway. Methods Mice were randomly allocated into Ad-GFP group, Ad-IRF-1 group, Ad-IRF-1+ SB203580 group and Control group, with ten mice in each group. In Ad-GFP group, controlled GFP adenoviruses were injected into the mice via tail veins six hours before the operation. In Ad-IRF-1 group, adenoviruses over expressing IRF-1 gene were injected into the mice the same way. In Ad-IRF-1+ SB203580 group, adenoviruses over expressing IRF-1 gene and P38 MAPK inhibitor SB203580 were injected into the mice. Control group received equal amount of normal saline. The hepatic IRI model was established. Then liver functions and histology by HE staining were observed after reperfusion, hepatocellular apoptosis was determined by TUNEL assay, PCNA protein was dyed by immunohistochemistry. AML12 cell lines were cultured and divided into Control group, GFP-NC group, GFP-IRF-1 group, siRNA-NC group and IRF-1 siRNA group. Controlled GFP or over express IRF-1 adenoviruses were propagated into cells in GFP-NC or GFP-IRF-1 group respectively. SiRNA-NC or IRF-1 siRNA group received null control or IRF-1 siRNA transfection respectively. Control group received equal amount of DMEM/F-12 medium. Simulate hepatic IRI model. Expressions of IRF-1, P38, p-P38 and Caspase-3 proteins were detected by western blot. Results Ad-IRF-1 group has significantly higher levels of serum ALT and AST compared with Ad-GFP group (P<0.05). The hepatic histological changes were aggravated the most in Ad-IRF-1 group, consisted of hepatocytes swelling, sinusoids narrowing, and large patchy necrosis. Ad-IRF-1 group also exhibited an increased hepatocellular apoptosis rate (P<0.05) and decreased PCNA expression than Ad-GFP group. In Ad-IRF-1+ SB203580 group, liver injury was milder, hepatocellular apoptosis rate was lower (P<0.05), and PCNA expression was higher. In AML12 cell lines, the expressions of IRF-1, p-P38 and Caspase-3 proteins were up-regulated in GFP-IRF-1 group compared with GFP-NC group; and down-regulated in IRF-1 siRNA group than that in siRNA-NC group. Conclusion IRF-1 promotes murine liver IRI, which may be related to activation of P38 MAPK and induction of hepatocellular apoptosis. Inhibition of IRF-1 expression or P38 activity may have a potential protective effect on murine hepatic IRI. Key words: Mice; Liver; Reperfusion injury; IRF-1; P38 MAPK