Ginsenoside Rb2 improves insulin resistance by inhibiting adipocyte pyroptosis

Figure 1.. Rb2 attenuated diet-induced obesity in C57BL/6 J mice. (a) Body weights of control mice and HFD-fed mice treated with or without Rb2 (40 mg/kg/d) for 10 days. (b) Weights of SAT and EAT after 10-day treatment. Performance of GTT (c), and ITT (e). Area under curve (AUC) of GTT (d) and ITT (f). (g) Phosphorylation (p-AKT) and total AKT levels in epididymal adipose tissue (EATs), ratio of phospho-AKT/total AKT. N = 5 per group. Data are presented as mean ± SEM, *P < 0.05, **P < 0.01 compared with CD+PBS group; #P < 0.05, ##P < 0.01 compared with HFD+PBS group

Figure 2.. Rb2 inhibited adipocyte pyroptosis in epididymal adipose tissue (EATs). (a) Increased mRNA expression levels of caspase 1, ASC, NLRP3, IL-1β and GSDMD in HFD-fed mice EAT, which can be ameliorated by Rb2. (b) Pro-caspase 1 and total caspase 1 levels, ratio of pro-caspase 1/caspase 1. (c) ASC, NLRP3 and GSDMD levels. (d) ASC staining from EAT secetion. N = 5 per group. Data are presented as mean ± SEM. *P < 0.05, **P < 0.01 compared with CD+PBS group; #P < 0.05, ##P < 0.01 compared with HFD+PBS group. GSDMD is a quintessential mediator of pyroptosis

Figure 3.. Rb2 promoted growth in 3T3-L1 adipocytes. Cell viability were measured by Cell Counting Kit-8 (CCK-8) in 3T3-L1 adipocytes with various Rb2 concentrations (10, 25, 50 or 100 μM) in the absence (a) or presence of TNF-α (5 ng/mL) (b). Data are presented as mean ± SEM. *P < 0.05, **P < 0.01 compared with control group; #P < 0.05, ##P < 0.01 compared with TNF-α group

Figure 4.. Rb2 improved insulin sensitivity in 3T3-L1 adipocytes. mRNA levels of adiponectin(a), GLUT4 (b) and IRS-1(c) in 3T3-L1 adipocytes. (d) Phosphorylation (p-AKT) and total AKT levels, p-AKT/AKT ratio in 3T3-L1 adipocytes. Data are presented as mean ± SEM. *P < 0.05, **P < 0.01 compared with control group; #P < 0.05, ##P < 0.01 compared with TNF-α group. BAY 11–7082 (BAY) is an NF-κB pathway inhibitor

Figure 5.. Rb2 inhibited pyroptosis in 3T3-L1 adipocytes. (a) mRNA levels of caspase 1, ASC, NLRP3, IL-1β and GSDMD. (b) Pro-caspase 1 and caspase 1, ratio of pro-caspase 1 to caspase 1. (c) ASC, NLRP3 and GSDMD levels in 3T3-L1 adipocytes. Data are presented as mean ± SEM. *P < 0.05, **P < 0.01 compared with control group; #P < 0.05, ##P < 0.01 compared with TNF-α group. GSDMD is a quintessential mediator of pyroptosis

Figure 6.. Rb2 inhibited NF-κB pathway both in epididymal adipose tissue (EATs) and 3T3-L1 adipocytes. Phosphorylation (p-P65) and total NF-κB/P65 (P65) levels in EATs (a) and 3T3-L1 cells (c); Phosphorylatio (p-IκBα) and total IκBα levels in EATs (b) and 3T3-L1 cells (d). Data are presented as mean ± SEM. (a-b) *P < 0.05, **P < 0.01 compared with CD+PBS group; #P < 0.05, ##P < 0.01 compared with HFD+PBS group; (c-d)*P < 0.05, **P < 0.01 compared with control group; #P < 0.05, ##P < 0.01 compared with TNF-α group