Role of STAT3 in hepatocyte regeneration after acetaminophen-induced hepatocellular injury in mice / 临床肝胆病杂志

ABSTRACT

ObjectiveTo investigate the role of STAT3 in hepatocyte proliferation after acetaminophen (APAP)-induced hepatocellular injury in mice. MethodsNormal mouse AML12 hepatocytes were cultured in vitro and were stimulated by APAP (1, 2.5, 5, 10, and 20 mmol/L) for 12, 24 or 48 hours, and the hepatocytes treated with an equal volume of phosphate buffered saline were established as control group. After the optimal stimulation concentration and duration of action were screened out, AML12 hepatocytes were treated with AG490 (10, 50, and 100 μmol/L). The CCK-8 assay was used to measure the viability of AML12 hepatocytes; RT-PCR was used to measure the mRNA expression levels of PCNA, CyclinD1, and Ki67 in AML12 hepatocytes, and Western blot was used to measure the protein expression levels of STAT3, p-STAT3, PCNA, and CyclinD1. A one-way analysis of variance was used for comparison of continuous data between multiple groups, and the least significant difference t-test was used for further comparison between two groups. ResultsAfter 24 and 48 hours of APAP treatment, compared with the control group, all concentration groups had a significant reduction in the viability of AML12 hepatocytes (all P＜0.05), with a viability of 0.717±0.0271 and 0.752±0.0141, respectively, when the concentration of APAP was 2.5 mmol/L, which was significantly different from that in the control group (all P＜0.05) and met the conditions of subsequent experiment. Compared with the control group, the 24-hour APAP (2.5 mmol/L) group had significant reductions in the mRNA expression of PCNA, CyclinD1, and Ki67 (all P＜0.01); compared with the 24-hour APAP group, the 48-hour APAP (2.5 mmol/L) group had significant increases in the mRNA expression of PCNA, CyclinD1, and Ki67 (all P＜0.01); therefore, a model of hepatocyte regeneration after in vitro AML12 hepatocyte injury was established by stimulation with APAP 2.5 mmol/L for 48 hours. After the addition of AG490, there was no significant difference in viability between the control group and the 10 and 50 μmol/L AG490 groups, and the other groups had a significant reduction in viability (all P＜0.01); compared with the APAP group, the AG490 (50 μmol/L)+APAP group and the AG490 (100 μmol/L)+APAP group had a significant reduction in viability (P＜0.01); therefore, 50 μmol/L AG490 was selected as the concentration for subsequent experiment. Compared with the control group, the APAP group had a significant increase in the protein expression level of p-STAT3 (P＜0.01), while the AG490 group and the APAP+AG490 group had a significant reduction (both P＜0.05); compared with the APAP group, the APAP+AG490 group had significant reductions in the protein expression levels of PCNA and CyclinD1 and the mRNA expression levels of PCNA, CyclinD1, and Ki67 (all P＜0.05). ConclusionSTAT3 participates in hepatocyte proliferation after APAP-induced hepatocyte injury in mice, while AG490, as an STAT3 inhibitor, can inhibit hepatocyte proliferation after APAP-induced hepatocyte injury by inhibiting the phosphorylation of STAT3.