蓝刺头对实验性Ⅱ型糖尿病大鼠降血糖作用机制的研究

With the errror of people's lifestyles and pets feeding management, it showed an increasing trend to humans and pets of diabetes in recent years, that is halmful to humans and pets health.But at the moment,the western medicine were widely used have different toxicity and side effects. While for Chinese medicine they have unique advantages and fewer side effects because it's meridian is clear and also with good systemic effect adjustment, correction of endocrine disorders. Echinops rich in natural resources, in the past the main application and research of it is in detoxification,anti-inflammatory,treatment of carbuncles, etc., its reducing blood sugar effect were rarely explored and reported. In this study, based on the preliminary results of reducing blood sugar, further to study the dose-effect relationships of Echinops extract for reducing blood sugar, and to optimize the extraction process for active ingredients. Meanwhile the experimental type Ⅱ diabetic rats for the study subjects, to study intestinal mucosa absorption of enzymes, pancreatic tissue apoptotic factor, the changs for insulin receptor number and sensitivity, the hormones related glucose metabolism and the key enzymes of glucose metabolism pathway in cell, to explore the mechanism of reducing blood sugar of Echinops. The results will provide fuller, more comprehensive theoretical basis for further broaden the findings on pharmacological effects and clinical applications and to enhance their medicinal value of Echinops, while for the full use of human and animal diabetes drug development and natural resources it has important theoretical significance and practical value.

随着人们生活方式及宠物饲养管理上的错位，糖尿病在两者间呈逐年上升的趋势，给人类及宠物的健康带来巨大的影响，然目前广泛使用的降糖西药均有不同程度的毒副作用。而中药归经明确、有良好的全身性调整作用，对内分泌紊乱的纠正有独特的优势，且副作用小。蓝刺头自然资源丰富，以往主要在清热解毒、抗炎、治痈肿等方面应用与研究，其降糖作用未见探索和报道。本研究在前期首肯其降糖效果基础上，进一步研究明确蓝刺头提取物降糖作用的量效关系，优化降糖有效成分的提取工艺，同时以实验性Ⅱ型糖尿病大鼠为研究对象，通过小肠黏膜吸收酶、胰腺组织及其细胞凋亡因子、胰岛素受体数量及敏感性变化、糖代谢相关激素及细胞糖代谢通路中关键酶的研究，探索蓝刺头降糖作用机制。研究结果为进一步拓宽蓝刺头的药理作用和临床应用范围、提升其药用价值提供充实、全面的理论依据，同时对于人畜糖尿病新药开发及自然资源的充分利用具有重要的理论指导意义和实际应用价值。

本研究针对蓝刺头提取物多糖B的降糖作用分别从体内和体外两个方面进行了研究。体内试验是以雄性SD大鼠作为Ⅱ型糖尿病动物模型，对其采食量、饮水量、和糖脂代谢相关生化指标进行了检测，定期杀鼠，采其肝脏和胰腺进行了组织学检测。结果显示，蓝刺头提取物多糖B高、中、低剂量组均能显著增高大鼠体重，肌、肝糖原含量。血液生化指标显示，蓝刺头多糖B各个剂量组均能显著升高血液中胰岛素的水平；且蓝刺头多糖B高、中剂量组对大鼠的胰高血糖素、糖化血红蛋白含量、脂肪酸和肿瘤坏死因子-α均有积极的改善作用。组织学检测显示，蓝刺头多糖B对Ⅱ型糖尿病所造成的肝脏和胰腺的损伤有一定程度的修复作用。免疫组化结果显示蓝刺头多糖B通过上调胰岛，肝脏和骨骼肌的胰岛素受体、胰岛素受体底物-1、胰岛素受体底物-2来改善胰岛素抵抗。蓝刺头多糖B体外试验主要培养了INS-1胰岛β细胞，HepG2人肝癌细胞，L6大鼠成肌细胞。蓝刺头多糖B具有保护氧化应激引起的INS-1胰岛β损伤的功能，且具有促其生长的作用。进一步研究其机理表明，蓝刺头多糖B是通过促进抑制凋亡蛋白Bcl-2的表达和抑制促凋亡蛋白Bax, caspase-3的表达等来抑制氧化应激引起的INS-1细胞凋亡的。蓝刺头多糖B能够促进INS-1细胞分泌胰岛素，进一步检测显示其胰岛十二指肠同源盒-1和胰岛素受体底物-2的基因表达量上升，提示了蓝刺头多糖B促胰岛素分泌的潜在分子机制。用棕榈酸体外制造胰岛素抵抗HepG2细胞和L6细胞模型。蓝刺头多糖B对胰岛素抵抗HepG2细胞的糖代谢没有明显的改善作用，而对胰岛素抵抗L6细胞则有明显的促进葡萄糖摄取的功效。通过研究与胰岛素抵抗关系密切的两条信号通路PI3K/AKT信号通路和AMPK信号通路，表明蓝刺头多糖B与AMPK信号通路有一定的协同性从而促进了细胞的葡萄糖摄取。从上述试验结果可以看出，蓝刺头对Ⅱ型糖尿病无论是恢复胰岛β细胞分泌功能，还是提高外周组织敏感性方面均有一定的促进作用，同时也佐证了中药在修正内分泌紊乱病症上有其优势，值得深入研究。