基于mTOR信号通路对胰岛自噬的影响探讨消渴“内热伤脺”的病机及滋阴清热中药的调控机制

Recent research findings reported that the main reason causing decreased number of islet beta cells in Type 2 diabetes mellitus is the autophagy mediated apoptosis(autophagic apoptosis),and Autophagy regulate the sensitivity of insulin ;mTOR is the key signaling molecules to regulate autophagy and cell proliferation.The Yunvjian, one of the remedies for nourishing Yin and clearing heat, has been widely used clinically for the treatment of.diabetes.Our preliminary study findings show that Yunvjian can reduce the blood glucose and the expression of autophagic gene LC3 and Beclin of pancreatic islet and proliferation Of islet cells and restoration of pancreatic islet morphology for the rats with spontaneous Type 2 diabetes mellitus (GK rats); however its mechanism of signal transduction pathways remains unknown. Therefore we propose to use morphological and molecular biology technique to conduct a study to:Observe the overall impact of the application of Yunvjian intervention on GK rats on the signal mechanism through the mTOR regulation of autophagy, and on pancreatic islet beta cell proliferation as well as the apoptosis of autophagic cells.Further explore the signaling mechanisms of mTOR regulation of autophagy and the effect of the autophagy on pancreatic islet beta cell proliferation and the apoptosis of autophagic cells, by letting Yunvjian contained serum takes effect on the cultured beta cells in high glucose, which is combined with the mTOR signaling pathway orautophagy modulators.This study will provide the first scientific evidence of using traditional Chinese medicine for the treatment of Type 2 diabetes mellitus from the perspective of mTOR regulation of autophagy,and The preliminary mechanism to explore the curative effect of Yunvjian in the treatment of T2DM;and The diabetes pathogenesis of "heat injuring pancreas” .

最新研究发现由自噬介导的细胞凋亡（自噬性细胞凋亡）是2型糖尿病胰岛细胞数量减少的主要原因之一;自噬参与调节机体对胰岛素的敏感性；mTOR是调控自噬及细胞增殖的关键信号分子。我们前期研究发现滋阴清热方玉女煎降低自发性T2DM大鼠（GK大鼠）血糖，降低胰岛自噬基因LC3和Beclin的表达，促进胰岛细胞增生，但其信号调控机制未明，且阴虚所生的内热如何形成消渴也未见论述。为此我们拟采用形态学及分子生物学等技术，首先用玉女煎干预GK大鼠，其次拟用玉女煎含药血清作用于高糖培养的β细胞，并结合mTOR信号通路的调节剂，观察其通过mTOR信号通路调控自噬、促进胰岛β细胞增殖及降低自噬性细胞凋亡的机制；初步揭示滋阴清热药的作用机制及消渴“内热伤膵”的病机。

糖尿病发病率在全球范围内有明显升高的趋势，成为严重威胁人类健康的慢性疾病。尽管各种降糖药物以及胰岛素对血糖调节有很好的作用，不少患者仍然持续进展并出现各种并发症。最新研究发现由自噬介导的细胞凋亡（自噬性细胞凋亡）是2型糖尿病胰岛细胞数量减少的主要原因之一;自噬参与调节机体对胰岛素的敏感性；mTOR是调控自噬及细胞增殖的关键信号分子。玉女煎出自《景岳全书》，功效滋阴清热，我们前期研究表明玉女煎可降低自发性 2 型糖尿病大鼠（Gk 大鼠）的血糖，降低胰岛自噬基因 LC3 和 Beclin 的表达，并促进胰岛细胞的增殖，胰岛细胞间结缔组织减少，使胰岛形态逐步恢复。结果表明，中剂量玉女煎对降低血糖和改善 GK 大鼠肾损伤有较好的效果，其次是降低 mTOR 水平。 肾皮质自噬水平增强，伴随体内细胞凋亡增加。此外，在 GK 大鼠中，玉女煎显着调节了调节自噬和细胞凋亡的蛋白质。然后，我们发现降低内源性 mTOR 可以逆转玉女煎对体内足细胞凋亡和自噬的影响。玉女煎含药血清能促进INS-1细胞的增殖并减少INS-1细胞的凋亡。自噬途径对 INS-1 细胞中的糖脂毒性至关重要。玉女煎含药血清通过调节自噬基因的表达和恢复自噬通量对 HG/HL 条件下培养的 INS-1 细胞具有保护作用。因此发现玉女煎通过 mTOR 信号通路调控胰岛β细胞自噬，减少其凋亡并促进其增殖以及改善胰岛素抵抗的分子机制，从而初步揭示滋阴清热药的作用机制及消渴“内热伤膵”的病机及物质基础。