Supplementary Material for: Glycyrrhizin, a High-Mobility Group Box 1 Inhibitor, Improves Lipid Metabolism and Suppresses Vascular Inflammation in Apolipoprotein E Knockout Mice

Background: High-mobility group box protein 1 (HMGB1) is known to have proinflammatory properties; however, the mechanisms by which HMGB1 influences immune responses during atherosclerosis (AS) development are not well understood. Thus, this study investigated the relationship between HMGB1 and vascular inflammation in Apoe–/– mice and whether glycyrrhizin (GLY), a small inhibitor of HMGB1, could have atheroprotective effects in AS. Methods: Apoe–/– mice on a high-fat diet were treated with GLY (50 mg/kg) or vehicle by gavage once daily for 12 weeks, respectively. Results: The GLY group exhibited significantly decreased serum lipid levels, atherosclerotic plaque deposition, and serum HMGB1 levels, as well as an increased Treg/Th17 ratio. The GLY group displayed increased interleukin-10 (IL-10) and IL-2 expression and decreased IL-17A and IL-6 expression. Furthermore, the GA treatment significantly reduced STAT3 phosphorylation in Th17 cells and increased STAT5 phosphorylation in Treg cells. Conclusions: Our findings indicate that the attenuation of atherosclerotic lesions in Apoe–/– mice by GLY might be associated with the amelioration of lipid metabolism abnormalities, inhibition of HMGB1 expression, and alterations in the Treg/Th17 ratio.

背景：高迁移率族蛋白B1（high-mobility group box protein 1, HMGB1）已被证实具有促炎特性，但HMGB1在动脉粥样硬化（atherosclerosis, AS）发生过程中影响免疫应答的具体机制尚未完全阐明。因此，本研究旨在探讨Apoe–/–小鼠中HMGB1与血管炎症的关联，以及HMGB1的小分子抑制剂甘草酸（glycyrrhizin, GLY）是否对动脉粥样硬化具有抗损伤保护作用。方法：高脂饮食喂养的Apoe–/–小鼠分别以灌胃方式每日给予GLY（50 mg/kg）或溶剂对照，连续干预12周。结果：GLY干预组的血清脂质水平、动脉粥样硬化斑块沉积量及血清HMGB1水平均显著降低，同时Treg/Th17细胞比值升高；该组白细胞介素-10（interleukin-10, IL-10）与IL-2的表达水平上调，而IL-17A及IL-6的表达水平下调。此外，GLY处理可显著降低Th17细胞中信号转导与转录激活因子3（signal transducer and activator of transcription 3, STAT3）的磷酸化水平，并上调Treg细胞中STAT5的磷酸化水平。结论：本研究结果显示，GLY可减轻Apoe–/–小鼠的动脉粥样硬化病变，其作用机制可能与改善脂质代谢异常、抑制HMGB1表达以及调节Treg/Th17细胞比值密切相关。