β-arrestin2 Inhibits Apoptosis and Inflammation of Liver Induced by Ischemia-reperfusion in Mice via AKT and TLR4 Pathway

Background Liver ischemia and reperfusion (I/R) is a common but severe clinical problem. Previous studies have revealed that the expression level of β-arrestin2 affects serum deprivation (SD)-induced cell apoptosis and was involved in lipopolysaccharide (LPS) stimulated TLR4 signaling pathway. However, little is known about β-arrestin2 in liver apoptosis and immune response induced by I/R. Methods A non-lethal model of segmental (70%) hepatic ischemia was utilized. Histology examination, cell apoptosis and cytokine levels were measured using H&E staining, TUNEL assay, and ELISA, respectively. Apoptosis-related protein and gene level of cytokines were respectively detected using Western blot and Real-time PCR. Results Our data showed that knockout (KO) of β-arrestin2 gene significantly deteriorated the injury of liver caused by I/R according to liver histology, higher serum liver enzyme, and increased level of cell apoptosis. β-arrestin2 KO could result in increased level of apoptosis related protein and decreased level of Akt phosphorylation. Furthermore, decreased levels of Bcl-2 and Bad phosphorylation, but increased level of Bax were found in β-arrestin2 KO group. In addition, the levels of p-ERK1/2, p-p38MAPKs, and p-NF-κB in β-arrestin2 KO group were significantly higher than that in WT group. Conclusions β-arrestin2 protected liver from I/R injury and this effect may be due to the regulating of Akt pathway, Bcl-2/Bax ratio, MAPKs and NF-κB pathway.