The protective effects of CHIR99021 against oxidative injury in LO2 cells

Hepatic ischemia-reperfusion injury is one of the most important factors for the prognosis of liver transplantation and hepatic surgery. It was reported that glycogen synthase kinase-3 (GSK-3) regulated injury response during ischemia-reperfusion. In this study, we investigated the protective effects of the GSK-3 inhibitor CHIR99021 against hepatic ischemia-reperfusion injury. A H2O2-induced oxidative injury model using LO2 cells was established. LO2 cells were divided into four groups, including blank control group, CHIR99021 control group treated with CHIR99021 alone, H2O2-injury group treated with H2O2 and protection group treated with H2O2 plus CHIR99021. Cell viability, cell apoptosis or necrosis was determined. Meanwhile, mitochondrial membrane potential, lipid peroxidation, cellular ROS levels, SOD activity, and serum contents of ALS and AST were measured. Protein and mRNA expressions were also detected. The results showed that a cell oxidative injury model was established by treating LO2 cells with 200 μmol/L H2O2 for 6 h. Cells exposed to H2O2 resulted in a significant decrease of cell viability and increase of cell apoptosis, which was accompanied by increasing ROS levels, disruption of mitochondrial membrane potential, excessive lipid peroxidation, reduction of SOD activity, and increased levels of ALT and AST. Treatment with CHIR99021 significantly protected LO2 cells against H2O2-induce oxidative injury by inhibiting the changes of above oxidative injury related indicators. Moreover, CHIR99021 treatment significantly reversed H2O2-induced decrease in p-GSK-3βSer9 , Bcl-2, Bcl-xl, survivin and β-catenin expression, whereas it significantly attenuated H2O2-induced increase in caspase-3, cleaved caspase-3 and p-JNK protein expression. In conclusion, CHIR99021 protected LO2 cells against H2O2-induced oxidative injury through reducing GSK-3β activity and apoptosis, with underlying mechanisms involved in stabilizing mitochondrial membrane potential, attenuating cellular ROS generation, suppressing mitochondria-mediated apoptotic pathway, and activation of GSK-3β/β-catenin signaling pathway.