L-阿拉伯糖对骨骼肌胰岛素PI3K通路的影响

发布时间：2019-03-27 21:01

【摘要】：L-阿拉伯糖是一种五碳醛糖,研究表明,它具有降血糖、血脂、血压,减少内脏器官脂肪积累、减缓体重增长等多种生物活性,被广泛应用于食品、医学、化工等多种领域。本文以糖尿病大鼠为实验模型,通过对实验大鼠状态和股四头肌组织病理切片的观察、相关生理生化指标及分子水平基因表达量的测定,研究了L-阿拉伯糖对糖尿病大鼠骨骼肌胰岛素PI3K通路的影响以及其可能的影响机理。首先,利用饲喂高糖高脂饲料结合尾静脉注射小剂量(30mg/(kg·bw))链脲佐菌素(STZ)的方法建立2型糖尿病模型,并以不同剂量(87.5mg/(kg·bw)、175mg/(kg·bw)、 525mg/(kg·bw))对糖尿病大鼠灌胃L-阿拉伯糖,对L-阿拉伯糖的降糖作用进行研究。结果显示,L-阿拉伯糖中剂量组(175mg/(kg·bw))和高剂量组(525mg/(kg·bw))可显著降低糖尿病大鼠的血糖值,提高糖尿病大鼠的糖耐量；L-阿拉伯糖对照组和中剂量组(175mg/(kg·bw))可分别显著降低正常和糖尿病大鼠糖化血清蛋白的含量；L-阿拉伯糖各剂量组可显著降低糖尿病大鼠血清中胰岛素的水平,改善胰岛素抵抗,且各组之间呈现一定的量效关系；L-阿拉伯糖中剂量组(175mg/(kg·bw))和高剂量组(525mg/(kg·bw))可显著降低糖尿病大鼠血清中C肽的水平,提高胰岛素的生物效应。其次,通过对实验大鼠股四头肌冷冻切片的制备、骨骼肌中的总超氧化物歧化酶(T-SOD)活力和丙二醛(MDA)含量及胰岛素PI3K通路信号转导相关蛋白水平的测定,对L-阿拉伯糖改善糖尿病大鼠骨骼肌的作用进行研究。结果显示,L-阿拉伯糖可明显提高股四头肌中氧化型肌纤维的比例,从而提高骨骼肌对葡萄糖的摄取和利用；结合对实验大鼠血清、骨骼肌中T-SOD活力和MDA含量的测定可知,在本实验的剂量范围内,L-阿拉伯糖对糖尿病的氧化应激无显著性影响；L-阿拉伯糖各剂量组可提高蛋白激酶B(PKB)和葡萄糖转运蛋白4(GLUT4)的水平且各组之间具有一定的量效关系,但只有高剂量组(525mg/(kg·bw))有显著性差异。最后,通过对实验大鼠骨骼肌中磷脂酰肌醇-3-激酶(PI3K)、蛋白激酶B(PKB,也称Akt)、葡萄糖转运蛋白4(GLUT4) mRNA的荧光实时定量PCR实验,对可能的相关机理进行探究。结果显示,与模型对照组比较,L-阿拉伯糖高剂量组(525mg/(kg·bw))能显著提高糖尿病大鼠骨骼肌中胰岛素PI3K通路主要信号转导蛋白基因mRNA的表达量,增强胰岛素PI3K通路的信号传递,进而提高骨骼肌对胰岛素的敏感性。
[Abstract]:L-arabinose (L-arabinose) is a kind of five-carbon aldehydes. It has been widely used in many fields such as food, medicine, chemical industry and so on because it has many biological activities, such as lowering blood sugar, blood lipid, blood pressure, reducing accumulation of fat in internal organs, slowing down weight gain and so on. In this paper, diabetic rats were used as experimental model. By observing the state and pathological sections of quadriceps femoris muscle, the relative physiological and biochemical indexes and the expression of genes at molecular level were determined. The effects of L-arabinose on insulin PI3K pathway in skeletal muscle of diabetic rats and its possible mechanism were studied. 30mg/ (kg 路bw) streptozotocin (STZ) was used to establish the model of type 2 diabetes mellitus. Different doses (87.5mg/ (kg 路bw),) were used to establish the model of type 2 diabetes mellitus (T2DM) by feeding high glucose and high fat diet combined with low dose (kg 路bw),). 175mg/ (kg 路bw), 525mg/ (kg 路bw) was used to study the hypoglycemic effect of L-arabinose (L-arabinose) on diabetic rats. The results showed that L-arabinose medium dose group (175mg/ (kg 路bw) and high dose group (525mg/) (kg 路bw) could significantly reduce the blood glucose value of diabetic rats and increase the glucose tolerance of diabetic rats; The content of glycosylated serum protein in normal and diabetic rats was significantly decreased by 175mg/ (kg 路bw) in L-arabinose control group and middle dose group (L-arabinose). Each dose of L-arabinose could significantly reduce the level of insulin in the serum of diabetic rats and improve the insulin resistance, and there was a dose-effect relationship among the groups. L-arabinose medium dose group (175mg/ (kg 路bw) and high dose group (525mg/) (kg 路bw) could significantly reduce the level of serum C-peptide and increase the biological effect of insulin in diabetic rats. Secondly, through the preparation of frozen sections of quadriceps femoris muscle, the activity of total superoxide dismutase (T-SOD) and the content of malondialdehyde (MDA) in skeletal muscle and the level of signal transduction related protein of insulin PI3K pathway in skeletal muscle were measured. The effect of L-arabinose on improving skeletal muscle of diabetic rats was studied. The results showed that L-arabinose could significantly increase the proportion of oxidized muscle fibers in quadriceps femoris and thus increase the uptake and utilization of glucose in skeletal muscles. Combined with the determination of T-SOD activity and MDA content in serum and skeletal muscle of experimental rats, it was found that there was no significant effect of L-arabinose on oxidative stress of diabetes mellitus in the dose range of this experiment. The levels of protein kinase B (PKB) and glucose transporter protein 4 (GLUT4) were increased in each dose group of L-arabinose, and there was a dose-effect relationship among the groups, but only the high dose group (525mg/ (kg 路bw) had significant difference. Finally, the mechanism of phosphatidylinositol-3-kinase (PI3K), protein kinase B (PKB, also known as Akt), glucose transporter 4 (GLUT4) mRNA, was studied by real-time fluorescence quantitative PCR. The results showed that compared with the model control group, 525mg/ (kg 路bw) could significantly increase the expression of the main signal transduction protein gene mRNA of insulin PI3K pathway in skeletal muscle of diabetic rats. Enhance the signal transduction of insulin PI3K pathway, and then improve the sensitivity of skeletal muscle to insulin.
【学位授予单位】：天津科技大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：R151

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