β-arrestin-2 alleviates mouse hepatic ischemia-reperfusion injury by inhibiting autophagy

  Objective  To investigate the impact of β-arrestin-2 on hepatic autophagy after ischemia-reperfusion(IR) and its effect on mouse hepatic ischemia-reperfusion injury(IRI).

  Methods  β-arrestin-2 wild type(WT) and knock out(KO) mice were used to build a mouse model of hepatic IR(70% hepatic warm ischemia for 90 min). Mice were divided into four groups: WT mice sham-operated group(WT+Sham group), WT mice IR group(WT+IR group), KO mice sham-operated group(KO+Sham group) and KO mice IR group(KO+IR group), 18 mice in each group. Serum and liver tissues were collected at 6, 12 and 24 h after reperfusion. The alanine aminotransferase(ALT), aspartate aminotransferase(AST) measurement and liver tissues hematoxylin-eosin(HE) staining and pathology analysis were used to estimate hepatic injury. The expression of light chain(LC)3, the key protein of autophagy, were detected by immunohistochemical(IHC) staining and western blot. Autophagosomes in liver tissues were evaluated by transmission electron microscopy(TEM).

  Results  Compared with Sham groups, the levels of serum ALT and AST significantly increased in IR groups at each time point (all in P < 0.01). The levels of KO+IR group were higher than those of WT+IR group at each time point (all in P < 0.01). The result of liver tissue HE staining showed that liver cell morphology and lobular architecture was normal in WT+Sham group and KO+Sham group at each time point after reperfusion. Liver cells were light or moderate swelling with liver sinus expansion in KO+IR group and WT+IR group at 6 h after reperfusion. And liver cells were severe swelling with inflammatory cells infiltration, and flake damage area is obvious at 12 h after reperfusion. Liver rope arranged regularly at 24 h after reperfusion. The degree of hepatic injury in KO+IR group was more serious than WT+IR group. IHC staining and western blot analysis showed that the expression levels of LC3 increased in IR groups at 6, 12 h but slightly decreased at 24 h after reperfusion. And the expression levels of KO+IR group were higher than WT+IR group. TEM result show that autophagosomes in IR groups were obviously more than those in Sham groups(both in P < 0.01). The counts of autophagosomes in KO+IR group were more than those of WT+IR group(P < 0.05).

  Conclusions  β-arrestin-2 may alleviate mouse hepatic IRI by inhibiting autophagy.