Protective role of magnesium isoglycyrrhizinate in non-alcoholic fatty liver disease and the associated molecular mechanisms.

Non-alcoholic fatty liver disease (NAFLD) is one of the most common liver diseases worldwide and there is an urgent need to identify effective pharmacological strategies to treat NAFLD. For this purpose, in the present study, we examined the the possible molecular mechanisms responsible for the effects of MgIG and the protective effects of MgIG in a model of NAFLD. The human hepatic L02 cell line and oleic acid were employed to establish an in vitro model of NAFLD. The CCK-8 assay, Hoechst 33258 staining and Annexin V-PI staining were performed in order to evaluate cell viability and apoptosis. Oil red O staining was used to detect lipid accumulation within the L02 cells. We found that MgIG significantly inhibited lipid accumulation and protected the L02 cells against lipid accumulation-induced apoptosis. Key molecules involved in unfolded protein response (UPR) signaling were upregulated in lipid-overloaded hepatic cells whereas MgIG suppressed the activation of the UPR. Furthermore, MgIG significantly inhibited the expression of the downstream inflammatory cytokines which had been induced by lipid accumulation. Taken together, these findings suggest that the activation of UPR signaling induces the expression of inflammatory cytokines through the activation of nuclear factor-κB (NF-κB) in lipid-overloaded hepatic cells. In addition, MgIG may suppress the activation of UPR signaling thereby protecting hepatic cells from NAFLD‑induced injury.