Glycyrrhizic acid ammonium salt alleviates Concanavalin A-induced immunological liver injury in mice through the regulation of the balance of immune cells and the inhibition of hepatocyte apoptosis

Abstract

Glycyrrhizic acid ammonium salt (GAAS) is derived from glycyrrhizic acid, which is an active compound extracted from the Chinese traditional medicine licorice. GAAS is clinically applied to treat immune-mediated liver injury, but its mechanism remains elusive. Therefore, this study aimed to investigate the mechanism in which GAAS alleviates immune-mediated liver injury induced by Concanavalin A (ConA). After ten days of intragastric administration of GAAS, 20 mg/kg ConA was injected via tail vein to establish the immune-mediated liver injury model of BALB/C mice. Then, the concentrations of ALT, AST, and TBIL in the serum of mice were determined. H&E staining was performed to observe the pathological changes in the liver, and the expression of liver cytokines was detected by qPCR. Immunohistochemistry and Western blot analysis was employed to detect the expression of liver-related proteins. The apoptosis in liver tissue was detected by TUNEL. Our results suggest that GAAS demonstrated excellent protective effects in the liver. We found that GAAS down-regulated the mRNA expression of IL-1β, IL-6, TNF-α, IFN-γ, and IL-17A, and it up-regulated the mRNA expression of IL-4 and TGF-β. Additionally, GAAS may modulate the balance of four immune cells (Th1, Th2, Th17, and Treg) by regulating the expression of T-bet, GATA3, RORγt, and Foxp3 to alleviate liver injury in mice. Furthermore, GAAS decreased hepatocyte apoptosis by blocking the JAK1/STAT1/IRF1 pathway, suppressing oxidative stress, decreasing p-JNK expression, and regulating the expression of apoptosis-related proteins. In summary, the mechanism of GAAS in liver injury alleviation acts to regulate the balance of Th cells in the liver to inhibit hepatocyte apoptosis. This study may provide a new strategy for the treatment of immune-mediated liver injury.