Horticulture and Landscape College, Hunan Agricultural University, Changsha, 410128, China; State Key Laboratory of Subhealth Intervention Technology, Changsha, 410128, China.
Horticulture and Landscape College, Hunan Agricultural University, Changsha, 410128, China; Hunan Key Laboratory of Crop Germplasm Innovation and Utilization, Hunan Agricultural University, Changsha, 410128, China.
J Ethnopharmacol. 2022 Feb 10;284:114790. doi: 10.1016/j.jep.2021.114790. Epub 2021 Nov 1.
Scutellaria baicalensis Georgi (SBG) is a traditional Chinese medicine with a remarkable remedial effect on diabetes mellitus. However, the precise mechanism involved has not been fully elucidated yet. Here, we aimed to explore the anti-diabetes effects of its traditional decoction in vitro and elucidate the autophagy-related mechanism.
This study was designed to investigate the effects of the water extract of SBG (WSB) on the β cell viability, insulin secretion and the mechanism related to autophagy.
Detection of insulin secretion using an enzyme immunoassay method, and analysis of apoptosis rate in MIN-6 cells by the flow cytometry with PI and Annexin V-FITC staining. In addition, the autophagy levels and pathways were evaluated from the number of autophagosomes and the expression of autophagy-related proteins. 3-Methyladenine (3-MA) was used as the autophagy inhibitor. Autophagosomes were observed using a confocal microscopy, and autophagy-related proteins (LC3-II/I, p62, S6k, p-AMPK/AMPK, p-mTOR/mTOR) were measured by Western blot.
Here we detected a significant increase in insulin release from MIN-6 cells after treated with WSB. It is about 1.6 times as much as that of the control group with 2.8 mM glucose and 2.2 times more than the 16.8 mM glucose group. At the same time, WSB increased the number of autophagosomes and the ratio of LC3 Ⅱ/LC3 Ⅰ, indicating that autophagy were activated in MIN-6 cells. When inhibiting autophagy, there was no significant difference in insulin release between the two groups. The apoptotic rate of the high glucose group was as high as 33.23%. After pretreatment with WSB, the apoptotic rate decreased to 14.95%, and increased to 22.57% when treated with 3-MA and WSB. At the same time, WSB treatment enhanced the phosphorylation of AMPK, but had no significant effect on the expression of mTOR and S6K.
Our data suggested that WSB increased insulin secretion and reduced apoptosis under high glucose by inducing autophagy through the AMPK pathway, which elucidated the mechanism of WSB in the treatment of diabetes.
黄芩（SBG）是一种传统中药，对糖尿病有显著的治疗作用。然而，其确切的作用机制尚未完全阐明。在这里，我们旨在研究其传统方剂在体外的抗糖尿病作用，并阐明与自噬相关的机制。
本研究旨在探讨黄芩水提取物（WSB）对β细胞活力、胰岛素分泌以及与自噬相关的机制的影响。
采用酶联免疫吸附法检测胰岛素分泌，PI 和 Annexin V-FITC 染色流式细胞术分析 MIN-6 细胞的凋亡率。此外，通过自噬小体数量和自噬相关蛋白的表达来评估自噬水平和途径。3-甲基腺嘌呤（3-MA）用作自噬抑制剂。通过共聚焦显微镜观察自噬体，并用 Western blot 测定自噬相关蛋白（LC3-II/I、p62、S6k、p-AMPK/AMPK、p-mTOR/mTOR）。
我们检测到 WSB 处理后 MIN-6 细胞胰岛素释放显著增加。在 2.8mM 葡萄糖组中，其胰岛素释放量约为对照组的 1.6 倍，在 16.8mM 葡萄糖组中，其胰岛素释放量约为对照组的 2.2 倍。同时，WSB 增加了自噬小体的数量和 LC3 Ⅱ/LC3 Ⅰ的比值，表明 MIN-6 细胞中的自噬被激活。当抑制自噬时，两组之间胰岛素释放没有显著差异。高糖组的凋亡率高达 33.23%。用 WSB 预处理后，凋亡率降低至 14.95%，而在用 3-MA 和 WSB 处理时，凋亡率增加至 22.57%。同时，WSB 处理增强了 AMPK 的磷酸化，但对 mTOR 和 S6K 的表达没有显著影响。
我们的数据表明，WSB 通过 AMPK 途径诱导自噬增加高糖下的胰岛素分泌并减少细胞凋亡，从而阐明了 WSB 治疗糖尿病的机制。
