脂肪间充质干细胞通过调节肝脏糖代谢改善2型糖尿病高血糖的机制研究

发布时间：2018-05-05 12:20

本文选题：间充质干细胞 + 高血糖　；参考：《中国人民解放军医学院》2017年硕士论文

【摘要】：随着发病率的不断增高,2型糖尿病已经成为危害人类健康的一大疾病,目前临床上治疗2型糖尿病的药物并没有针对糖尿病发病的中心环节。间充质干细胞(Mesenchymal stem cells, MSCs)作为一种具有自我复制和多向分化潜能的多能干细胞,已经被广泛运用于多种疾病的治疗,其中也包括糖尿病。大量的研究已经证实,MSCs输注可以相对持久和稳定地改善糖尿病高血糖,其主要机制是通过糖尿病发病的关键环节,即改善机体的胰岛素抵抗和增强β细胞的再生能力。在前期的研究中,我们观察到MSCs输注7天后2型糖尿病大鼠血糖明显下降,并且再次输注可以发挥持久和稳定的降糖效应,同时也惊讶地发现在细胞输注后的24小时内大鼠的血糖就出现了短暂而迅速的下降。系统胰岛素抵抗的改善和胰岛功能的恢复需要相对长期的一个过程,并不足以解释MSCs这种迅速的、短期的降糖效应,也就是说MSCs还有可能通过其他的分子机制发挥其降糖效应。因此对于MSCs降糖效应机制的进一步挖掘是非常有必要的,并可为其应用于临床提供更多的理论依据。本研究中,我们从正常大鼠的腹股沟脂肪组织中提取了脂肪间充质干细胞(Adipose-derived mesenchymal stem cells, ASCs),运用高脂喂养联合腹腔单次小剂量注射STZ建立2型糖尿病大鼠模型,随后经尾静脉输注了ASCs,着重观察细胞输注后24小时之内大鼠血糖的改变和胰岛素抵抗改善的情况。经动态观察我们发现,ASCs输注后第3个小时大鼠血糖开始明显下降,一直持续到24小时,同时大鼠肝脏组织中PI3K、pAKT的表达是被上调的,也就是说肝脏的胰岛素抵抗被改善,而从IPGTT和IPITT中我们并没有观察到系统性胰岛素抵抗的改善。进一步的机制研究我们发现:在细胞输注后的24小时之内,大鼠肝脏组织中糖原合成增加,糖酵解相关酶GK,PFK,PK的表达在不同时间点被不同程度上调,而糖异生相关酶PGC-1α, PEPCK和G6Pase的表达被下调。综合以上结果,说明ASCs这种迅速的降糖效应可能是通过调节了肝脏的糖代谢。在体外实验中我们利用PA刺激HepG2细胞建立了糖代谢异常模型,并将ASCs与之共培养,进一步证实ASCs可以在短时间通过调节肝脏糖代谢过程中一些关键因子的表达来降低葡萄糖生成。除此之外,我们还发现ASCs是通过促进肝脏组织中AMPK的磷酸化来调节肝脏糖代谢,从而迅速改善2型糖尿病高血糖的。通过本研究,我们发现ASCs输注可以通过激活肝脏组织中的AMPK来促进肝脏糖原合成和糖酵解,以及抑制肝脏葡萄糖产生,最终降低2型糖尿病大鼠高血糖,为间充质干细胞治疗2型糖尿病提供了新的研究线索和理论依据。
[Abstract]:With the increasing incidence of type 2 diabetes, type 2 diabetes has become a major disease that endangers human health. At present, there is no central link in the clinical treatment of type 2 diabetes. Mesenchymal stem cells (MSCs) have been widely used in the treatment of many diseases, including diabetes mellitus, as a kind of pluripotent stem cells with self-replication and multi-differentiation potential. A large number of studies have proved that MSCs infusion can improve diabetes hyperglycemia relatively long and steadily, its main mechanism is to improve the body's insulin resistance and the ability of 尾 -cell regeneration through the key link of diabetes. In previous studies, we observed that blood glucose decreased significantly in type 2 diabetic rats after 7 days of MSCs infusion, and that repeated infusion played a lasting and stable hypoglycemic effect. It was also surprising to find that blood sugar levels in the rats decreased briefly and rapidly within 24 hours of cell infusion. The improvement of systemic insulin resistance and the recovery of islet function require a relatively long process, which is not sufficient to explain the rapid and short-term hypoglycemic effect of MSCs, which means that MSCs may exert its hypoglycemic effect through other molecular mechanisms. Therefore, it is necessary to further explore the mechanism of hypoglycemic effect of MSCs, and can provide more theoretical basis for its clinical application. In this study, we extracted adipose mesenchymal stem cells (Adipose-derived mesenchymal stem cells, ASCs1) from the inguinal adipose tissue of normal rats, and established a rat model of type 2 diabetes by high-fat feeding and single intraperitoneal injection of STZ. Then ASCs was injected via caudal vein to observe the changes of blood glucose and the improvement of insulin resistance in rats within 24 hours after cell infusion. After dynamic observation, we found that the blood glucose began to decrease significantly in the third hour after ASCs infusion and lasted until 24 hours. Meanwhile, the expression of PI3KPK pAKT was up-regulated in the liver of rats, which means that the insulin resistance of the liver was improved. No improvement in systemic insulin resistance was observed from IPGTT and IPITT. We found that within 24 hours after cell infusion, glycogen synthesis was increased, and the expression of glycolytic enzyme GK-PFK-PK was up-regulated at different time points. The expression of PGC-1 伪, PEPCK and G6Pase was down-regulated. These results suggest that the rapid hypoglycemic effect of ASCs may be mediated by regulation of glucose metabolism in the liver. In vitro, we established a model of abnormal glucose metabolism in HepG2 cells stimulated by PA and co-cultured with ASCs. It is further confirmed that ASCs can reduce glucose production by regulating the expression of some key factors in liver glucose metabolism for a short time. In addition, we found that ASCs regulates hepatic glucose metabolism by promoting the phosphorylation of AMPK in liver tissue, thereby rapidly improving hyperglycemia in type 2 diabetes. In this study, we found that ASCs infusion can promote hepatic glycogen synthesis and glycolysis by activating AMPK in liver tissue, and inhibit hepatic glucose production, and ultimately reduce hyperglycemia in type 2 diabetic rats. It provides a new clue and theoretical basis for the treatment of type 2 diabetes by mesenchymal stem cells.
【学位授予单位】：中国人民解放军医学院
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R587.1

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