Allograft inflammatory factor-1 is up-regulated in warm and cold ischemia-reperfusion injury in rat liver and may be inhibited by FK506.

Background: Allograft inflammatory factor-1 (AIF-1) plays an important role in immune response and vasculopathy in allografts. The present study investigated activation of AIF-1 in warm and cold ischemia-reperfusion (IR) injury of rat liver, and the potential inhibitory effect of FK506.

Methods: We used warm IR injury, orthotopic transplantation, and allograft rejection models in this study. We assessed expression of AIF-1 mRNA and protein, as well as its inducers interferon-γ (IFN-γ) and interleukin-1β (IL-1β). The potential inhibitory effect of FK506 on AIF-1 in a rat macrophage cell line and in these three models was also assessed.

Results: AIF-1 mRNA and protein, as well as its inducers IFN-γ and IL-1β, were significantly increased in the warm IR injury, orthotopic transplantation, and allograft rejection models. Real-time RT-PCR and Western blotting showed that pretreatment with low-dose FK506 partially inhibited AIF-1 activation as well as its inducers (IFN-γ and IL-1β) in these three models. Western blotting showed that IFN-γ and IL-1β activated AIF-1 in a macrophage cell line, but pretreatment with FK506 did not inhibit AIF-1 activation in vitro. Hematoxylin and eosin staining showed that edema and necrosis in the liver, as well as alanine aminotransferase (ALT) in serum, of these three groups was reduced after FK506 pretreatment.

Conclusion: AIF-1 was activated in warm and cold IR injury, and pretreatment with low-dose FK506 partly inhibited AIF-1 activation and reduced warm and cold IR injury.