Mild hypothermia pretreatment protects against liver ischemia reperfusion injury via the PI3K/AKT/FOXO3a pathway

Mild hypothermia is known to protect against ischemia and reperfusion (IR) injury. The exact mechanisms of the protection are not fully understood. Forkhead box O3 (FOXO3a) has been defined as a critical mediator in cellular processes, including oxidative stress, apoptosis, inflammation, cell death and DNA repair; however, the protection function in mild hypothermia has not been reported previously. The current study was designed to investigate the function of phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/FOXO3a pathway in pretreatment with mild hypothermia during IR injury. Additionally, PI3K/AKT/FOXO3a signaling was inhibited using Ly294002 and the effect on the protective function of mild hypothermia pretreatment was evaluated. Furthermore, the apoptotic and inflammatory response induced by the IR injury was evaluated. Liver IR injury induced a significant increase in the level of apoptosis and inflammatory responses. However, pretreatment with mild hypothermia increased phospho (p)-AKT and p-FOXO3a following IR injury, and significantly reduced apoptosis and inflammatory cytokines release. However, inhibiting p-AKT and p-FOXO3a using Ly294002 suppressed the liver protection produced by mild hypothermia. In conclusion, these findings indicated that mild hypothermia pretreatment exhibited liver protective effects against IR injury associated with suppressing inflammatory cytokine release and apoptosis via the PI3K/AKT/FOXO3a pathway.