Abstract: Objective To investigate the effect of transcription factor FOXO3a on mitophagy in hepatic ischemiareperfusion injury in mice. Methods A total of 30 male C57BL/6 mice were randomly divided into Sham operation group (Sham) and ischemia reperfusion (IR) 2 h, 6 h, 12 h and 24 h groups, 6 mice in each group. The mouse model of liver ischemia -reperfusion injury was established. Blood biochemical methods were used to detect changes of alanine aminotransferase (ALT) and aspartate aminotransferase (AST). HE staining and TUNEL were used to observe the damages of liver tissue and apoptosis. Western blot assay and qRT-PCR were used to detect the expressions of transcription factor FOXO3a, mitochondrial autophagy-related protein Nix protein and its mRNA expression in each group. Mouse liver AML12 cells were treated with FOXO3a and Nix interfering RNA, and the model was established for 6 h after hypoxia for 1.5 h.These cells were divided into siRNA-NC group, FOXO3a siRNA group and Nix siRNA group. MTT assay was used to detect the viability of cells in each group. The number and distribution of autophagy in each group were observed by confocal microscopy. The expressions of FOXO3a, Nix, microtubule-associated protein LC3, apoptotic protein P62 and Caspase-3 were detected by Western blot assay. Results The levels of ALT and AST in all groups of IR were reduced, and reached the peak value at 6 h (P＜0.05). HE and TUNEL results showed that liver injury and apoptosis were the most serious at 6 h after reperfusion. The expression of FOXO3a and Nix was higher in IR group than that in the Sham group, and the expression level of FOXO3a mRNA was the highest at 12 h after reperfusion, the expression of Nix mRNA was the highest at 6 h after reperfusion (P＜0.05). Western blot assay showed the highest expression of FOXO3a in the reperfusion of 12 h, and the highest expression levels of Nix, Caspase-3 and LC3Ⅱin reperfusion 6 h. After interfering with the expression of FOXO3a, MTT showed a marked reduction in cell survival (P＜0.05), Western blot assay showed that the expression level of FOXO3a was significantly higher in siRNA-NC group than that in FOXO3a siRNA group, and the expression levels of Nix, Caspase-3 and LC3Ⅱwere significantly lower than those of FOXO3a siRNA group. Confocal microscopy showed that the number and distribution of autophagosomes were significantly lower in siRNA-NC group than those in FOXO3a siRNA group. After interfering with the expression of Nix, MTT showed a marked increase in cell survival (P＜0.05), Western blot assay showed that the expression levels of Nix, P62 and LC3Ⅱ were significantly higher in siRNA-NC group than those in Nix siRNA group. Conclusion FOXO3a can reduce the hepatic ischemia-reperfusion injury in mice, which may be related to the FOXO3a inhibition for liver cell mitophagy and apoptosis.

Key words: FOXO3a, mitophagy, ischemia-reperfusion injury, apoptosis