Magnesium isoglycyrrhizinate prevents the nonalcoholic hepatic steatosis via regulating energy homeostasis

FIGURE 1. The protective effect of magnesium isoglycyrrhizinate (MGIG) treatment on hepatic injury caused by high‐fat diet (HFD). The liver steatosis was induced by a HFD for 12 wk. The MGIG groups were intraperitoneally treated with MGIG (10 or 30 mg/kg) once a day for 6 wk since 7th week. The bodyweight, liver weight and the ratio of liver weight/bodyweight (A). The activities of alanine aminotransferase (ALT) and aspartate aminotransferase in serum (AST; B). The serum levels of glucose, triglyceride (TG) and total cholesterol (TC; C). The serum levels of low‐density lipoprotein cholesterol (LDL‐C) and high‐density lipoprotein cholesterol (HDL‐C; D). The hepatic levels of triglyceride (TG) and total cholesterol (TC; E). The data were presented as means ± SDs. Compared with Control group: # P < .05, ## P < .01, ### P < .001. Compared with Model group: *P < .05, **P < .01, ***P < .001 (n = 6)

FIGURE 2. Effects of magnesium isoglycyrrhizinate (MGIG) treatment on high‐fat diet (HFD)‐induced lipid accumulation in livers. Representative photographs of histopathologic changes are presented (A). Representative photographs of Oil Red O staining are presented (B). Ultramicrostuctures of mitochondria and lipid droplets in livers are presented by transmission electron microscopy (C). The data were presented as means ± SDs. Compared with Control group: # P < .05, ## P < .01, ### P < .001. Compared with Model group: *P < .05, **P < .01, ***P < .001 (n = 3)

FIGURE 3. Magnesium isoglycyrrhizinate (MGIG) improves energy metabolism via regulating the uptake of glutamate into tricarboxylic acid (TCA) cycle. Livers of each group were homogenized and mixed with 80% methanol solution containing 5‐13C‐glutamine for the following metabonomic analysis. The PLS‐DA plot of control, HFD model and MGIG groups for liver data (A). The sPLS‐DA 3D plot of control, HFD model and MGIG groups for liver data (B). Heatmaps exhibiting metabolites in livers of MGIG mice and HFD mice (C). The metabolites associated with glutamate and TCA cycle metabolic pathways in liver tissues after MGIG treatment (D). The data were presented as means ± SDs. Compared with Control group: # P < .05, ## P < .01, ### P < .001. Compared with Model group: *P < .05, **P < .01, ***P < .001 (Control: n = 8, HFD: n = 6; MGIG: n = 8)

FIGURE 4. Magnesium isoglycyrrhizinate (MGIG) treatment improved hepatic steatosis by promoting lipid metabolism. The hepatic levels of NAD+, NADH and NAD+/NADH ratio (A). The protein expression of deacetylase sirtuin 1 (Sirt1) and its quantification data in liver samples (B). The lipid synthesis‐related genes expressions (C). The lipid metabolism‐related genes expressions (D). The data were presented as means ± SDs. Compared with Control group: # P < .05, ## P < .01, ### P < .001. Compared with Model group: *P < .05, **P < .01, ***P < .001 (n = 6)

FIGURE 5. Inhibition in Toll‐like receptor 4 binding pathway was associated with the protective effect of magnesium isoglycyrrhizinate (MGIG) intervention. Transcriptome profiling was conducted to further find the differential gene between MGIG mice and high‐fat diet (HFD) mice. Heatmap exhibiting the reversion of MGIG treatment in gene expression (A). The left column represents the differential genes when MGIG vs HFD model group, and the right column represents the differential genes when HFD model vs control group. The clustering of significant differential genes between MGIG group and HFD model group to find the pathways these genes involved in (B). The gene expressions of Toll‐like receptors (TLRs) isoforms were evaluated (C). The expressions of TLR4‐related genes were assessed (D). The data were presented as means ± SDs. Compared with Control group: # P < .05, ## P < .01, ### P < .001. Compared with Model group: *P < .05, **P < .01, ***P < .001 (n = 6)

FIGURE 6. The anti‐inflammatory property of magnesium isoglycyrrhizinate (MGIG) accounts for its resistance to lipidation. The effects of MGIG on the protein expressions of HMGB1, TLR4, Myd88, the phosphorylation of NF‐κBp65 and activation of Nlrp3 inflammasome in liver tissues (A). The levels of TNF‐α, IL‐1β in serum (B). The data were presented as means ± SDs. Compared with Control group: # P < .05, ## P < .01, ### P < .001. Compared with Model group: *P < .05, **P < .01, ***P < .001 (n = 6)