五倍子中五没食子酰基葡萄糖抑制高糖状态下胰岛β细胞凋亡的机制研究

Type 2 diabetes is a chronic disease which could cause blindness, disability and death. Global prevalence of diabetes has increased sharply ,especially in china.Pancritic β cell apotosis is a main pathological base of onset and devolop of type 2 diabetes.The report recently showed that Txnip (thioredoxin-interacting protein) is a key factor of aptosis of pancreatic β cell , the Txnip-TRX interaction that under the condiction of hign concentration of glucose could regulate apotosis of pancreatic β cell .Some studies indicated that pentagalloyl-glucopyranose （β-PGG) could inhibited the nuclear factor-κB (NF-κB)which played an important role in the inflammation process . Rhus chinensis Mill is one of chinese traditional medecines which could treat diabetes, My studies showed that β-PGG which separated from Rhus chinensis Mill enhanced the survival rate of Ins-1 cells and increased the expression of TRX of Ins-1 cell and decreased the expression of caspase-9 of Ins-1 cell which under the condiction of hign concentrition of glucose.these results indicated that β-PGG could inhibited the apotosis of pancreatic β cell.It is necessary to study the mechanism of β-PGG inhibits apotosis of pancreatic β cell by mitigating the negative effect of glucotoxicity in mitochondria stress or endoplasmic reticulum stress and inflammation, and analyze how β-PGG to affect the variation of TXNIP,TRX and NFκB etc. It is important to find a potential natural compound that could treat type 2 diabetes complicated with pancreatic β cell failure.

2型糖尿病一种可致残、致盲、致死的慢性多发病，其患病率在中国明显增长。高糖状态下胰岛β细胞凋亡是2型糖尿病发生及发展重要的病理基础之一。近期研究显示：硫氧还蛋白相互作用蛋白（TXNIP）是促胰岛β细胞凋亡的关键因子，与硫氧还蛋白（TRX）相互作用影响高糖条件下胰岛β细胞的凋亡；五倍子是治疗糖尿病的传统用药之一，申请人的实验表明五倍子中的五没食子酰基葡萄糖（β-PGG）可增加高糖作用下Ins-1细胞的存活率、促使Ins-1细胞的TRX的表达、可抑制高糖条件下凋亡因子caspase-9的表达，故提示其有抑制胰岛β细胞凋亡的作用。有必要从线粒体途径、内质网途径、炎症应激方面研究β-PGG抑制葡萄糖毒性所致胰岛β细胞凋亡的机制，进一步明确β-PGG如何影响TXNIP、TRX、NFκB等而产生作用，为筛选有治疗糖尿病胰岛β细胞凋亡作用的天然化合物提供实验依据。

糖尿病患病率的日益增长已经成为医疗重任和社会热点。在2型糖尿病发生和发展过程中，胰岛β细胞凋亡这一病理基础尤为关键，TXNIP作为促凋亡因子，影响着葡萄糖毒性作用下的胰岛β细胞的线粒体应激、氧化应激及炎症反应，导致高糖状态下的胰岛β细胞凋亡。本课题研究中发现：五倍子中含有较丰富的β-PGG。β-PGG在一定PH值的条件下可以分解出没食子酸，Wistar大鼠腹腔注射β-PGG后可在胰腺组织中检测出β-PGG，STZ造模成功的Wistar糖尿病大鼠，腹腔注射β-PGG可在其胰腺组织中测试出β-PGG和没食子酸。本课题及应用MTT法及FCM法测定高糖条件下Ins-1细胞的凋亡率，加入β-PGG后其凋亡率下降，应用HE染色及橙黄G染色法检测β-PGG灌喂的STZ造模成功的Wistar糖尿病大鼠，结果显示β-PGG能够抑制β细胞凋亡。应用western法、PCR法测定对处于高糖条件下（D-Glucose24.98mM)及加入不同浓度的β-PGG的Ins-1细胞的促凋亡因子TXNIP及线粒体应激、内质网应激、炎症小体应激的相关因子Caspase12、Caspase9、Cytc、IL-6、JNK、NF-ΚB的mRNA、蛋白的表达均提示β-PGG可以有效抑制胰岛β细胞的凋亡。五倍子中β-PGG可以影响线粒体应激、内质网应激、炎症小体应激抑制高糖状态下的胰岛β细胞凋亡，可以作为治疗糖尿病的天然化合物之一。