代谢手术对糖尿病大鼠心肌功能的改善作用及机制研究

发布时间：2018-03-23 09:02

  本文选题：代谢手术　切入点：糖尿病心肌病　出处：《山东大学》2017年硕士论文　论文类型：学位论文

【摘要】：[研究背景]糖脂代谢障碍引起的心肌功能紊乱是糖尿病的严重并发症之一,目前尚无有效的治疗方法。近年来,代谢手术越来越普遍用于医治糖尿病及其并发症。其在改善、缓解糖尿病心肌病(diabetic cardiomyopathy,DCM))方面的有效性亦日益受到人们的重视,但是其机制还不清楚。普遍认为,内质网应激(endoplasmic retjculum stress,ERS)介导的细胞凋亡与DCM的病理进程息息相关。在糖尿病状态下,心肌细胞糖脂代谢异常,内质网的工作环境受到干扰,ERS启动欲纠正细胞的错误蛋白折叠,以维持细胞的正常功能。若干扰力量较大,ERS无法复原细胞的正常生理功能,便引发细胞凋亡程序,来维持机体的正常运转。为了研究代谢手术对DCM的缓解作用,探讨其相关机制,本研究在DCM动物模型基础上,明确代谢手术对糖尿病大鼠心肌功能的缓解作用,并通过对心肌细胞内质网应激通路相关蛋白表达变化的比较与分析,进一步探讨代谢手术后DCM缓解的机制。[研究方法]本实验以高脂饮食及小剂量链脲佐菌素(STZ)诱导的糖尿病大鼠为研究动物模型,分三组,分别施以十二指肠空肠旁路术(DJB)、袖状胃切除术(SG)、及假手术(SHAM)。各组观测指标包括:(1)测量术前术后各特定时间点的体重及全身的血糖、脂质水平;(2)行口服葡萄糖耐量实验(Oral glucose tolerance test,0GTT)和胰岛素耐量实验(Insulin tolerance test,ITT),比较代谢手术对糖尿病大鼠糖代谢的影响;(3)术后8周,行超声心动图检测,比较代谢手术对糖尿病大鼠心功能的影响情况;(4)行HE染色、Masson染色、油红0染色和Tunel染色,测量比较代谢手术后,心肌的形态学变化及细胞凋亡情况;(5)行免疫组化实验、wesetern blot 及qRT-PCR检测ERS信号分子GRP78、PERK、p-PERK、iRE1α、p-IRE1a、ATF6、CHOP 和 caspase12 的表达情况。[研究结果]1、成功给予三组大鼠相应手术,在整个实验过程中无大鼠死亡。2、术前,三组大鼠体重无差别;术后1周,三组大鼠体重下降至最低点,后逐步回升,DJB组与SHAM组大鼠体重回升幅度相当,在整个实验周期中,两组大鼠体重无统计学差别;SG组大鼠体重上升相对较缓,术后6周、8周,SG组大鼠体重与DJB组和SHAM组大鼠相比,差别达到统计学意义(P0.05)。3、术前,三组大鼠AUCOGTT与AUCITT无差别;术后2周、8周,DJB组与SG组大鼠AUCOGTT与AUCITT值显著低于SHAM组(P0.01),DJB组与SG组间无差别。4、术后8周,DJB组与SG组大鼠心功能较SHAM组显著改善,超声心动图结果表现为,DJB组与SG组LVEDd与LVPWd较SHAM组明显降低(LVEDd:P0.01;LVPWd:P0.001),LVEF、FS、E/A 较 SHAM 组明显升高 CLVEF:P0.01;FS:P0.05;E/A:P0.001);DJB 组与 SG 组间无差别。5、HE及Masson染色结果提示,代谢手术后,心肌细胞肥大、心肌纤维化情况较SHAM组缓解;油红0染色结果提示代谢手术不影响心肌细胞的脂质沉积。6、术后8周,DJB组与SG组大鼠心肌细胞凋亡率显著低于SHAM组(P0.001),DJB组与SG组间无差别。7、免疫组化、western blot及qRT-PCR结果均提示,代谢手术后,GRP78、CHOP、caspasel2及PERK、p-PERK明显低于SHAM组,DJB组与SG组间差别无统计学意义;三组间IRE1、p-IRE1及ATF6表达均无统计学差别。[研究结论]1、DJB与SG均可有效的改善糖尿病大鼠的糖耐量及胰岛素抵抗,缓解糖尿病大鼠的心肌功能。2、DJB与SG通过抑制PERK途径抑制糖尿病大鼠心肌细胞内质网应激,降低心肌细胞凋亡,从而改善心肌功能。3、DJB与SG在改善糖尿病大鼠心肌功能紊乱方面无差别。
[Abstract]:[background] myocardial dysfunction caused by lipid metabolism disorder is a serious complication of diabetes, there is no effective treatment. In recent years, more and more widely used in the treatment of metabolic surgery of diabetes and its complications. The improvement in ease of diabetic cardiomyopathy (diabetic) cardiomyopathy, DCM) effectiveness also has been paid more and more attention however, the mechanism is not clear. It is generally accepted that the endoplasmic reticulum stress (endoplasmic retjculum, stress, ERS) pathological process and cell apoptosis mediated by DCM are closely related. In the diabetic state, myocardial cell lipid metabolism, endoplasmic reticulum work environment is disturbed, ERS starting cell error correct protein folding, to to maintain the normal function of the cells. If the interference power is larger, the normal physiological function of ERS cells cannot be restored, will lead to cell apoptosis process, to maintain the body's normal In order to alleviate the effects of the operation. The metabolic surgery for DCM, to explore the underlying mechanism, based on the research of DCM animal model, clear metabolic surgery on myocardial function of diabetic rats relieving, comparison and analysis and expression of myocardial cells through endoplasmic reticulum stress related protein, to further explore the mechanism of metabolic research methods. After the operation of DCM mitigation] in this experiment, high fat diet and a low dose of streptozotocin (STZ) induced diabetic rats as animal model study, divided into three groups, were treated with duodenal jejunal bypass (DJB), sleeve gastrectomy (SG), and sham operation (SHAM). Each group included observation index: (1) blood glucose, body weight and the specific point in time measurement of preoperative and postoperative lipid level; (2) underwent oral glucose tolerance test (Oral glucose tolerance test, 0GTT) and insulin tolerance test (Insulin tolerance test, ITT ), to compare the effects of metabolic surgery on glucose metabolism in diabetic rats; (3) 8 weeks after operation, echocardiography detection, comparison of metabolic surgery on cardiac function in diabetic rats; (4) by HE staining, Masson staining, oil red 0 and Tunel staining, measurement of metabolic surgery after the morphologic changes and apoptosis in myocardium; (5) immunohistochemical experiments, ERS Wesetern and qRT-PCR blot detection signal molecules GRP78, PERK, p-PERK, p-IRE1a, iRE1 alpha, ATF6, the expression of CHOP and caspase12. On]1, the success of the three groups of rats given the corresponding operation in the whole experiment in the process of no rat died in.2, before the operation, the weight of rats in the three groups no difference; after 1 weeks, body weight of rats in the three groups decreased to the lowest point, after a gradual recovery in DJB group and SHAM group rats weight recovery rate is in the whole experimental period, no significant difference of body weight of rats in the two groups group SG rats; 閲嶄笂鍗囩浉瀵硅緝缂，

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