【作者】 朱玉；

【导师】 冯凭；

【作者基本信息】 天津医科大学 ， 内科学， 2010， 硕士

【摘要】 目的目前,在世界范围内糖尿病的发病呈流行趋势,成为严重威胁人类健康的全球性公共健康问题。糖尿病动脉粥样硬化是糖尿病患者的主要伴发病和首要死亡原因,深入研究其发生发展机制并予以积极的治疗成为目前医学界迫切需要解决的问题[1]。组蛋白去乙酰化酶(SIRT)1是近年发现的与衰老、糖尿病、动脉粥样硬化密切相关的核蛋白,最近的研究还发现其在维持血管正常功能中具有重要的作用。本研究以不同大鼠模型腹主动脉为研究对象,研究SIRT1的表达情况,以及二甲双胍对其表达的影响,探讨SIRT1在糖尿病动脉粥样硬化发生发展中的可能作用。内容1、以自发性2型糖尿病OLETF大鼠为研究对象,观察它与正常LETO大鼠腹主动脉在动脉粥样硬化中形态和结构的变化情况。2、研究OLETF大鼠腹主动脉内皮SIRT1表达情况,分析SIRT1在糖尿病动脉粥样硬化发生发展中的作用。3、以二甲双胍干预OLETF大鼠12周,观察二甲双胍干预以后大鼠腹主动脉病理变化及SIRT1表达情况,分析二甲双胍干预的作用。方法1、实验方法：自发性2型糖尿病OLETF大鼠成模；应用实时荧光定量PCR技术检测腹主动脉去乙酰化酶SIRT1的表达水平；病理常规石蜡包埋HE染色切片观察各组大鼠腹主动脉形态学变化。2、统计方法：采用SPSS16.0统计软件处理试验数据,所得数据以x±s表示,多组比较采用单因素方差分析,两两比较用Student-Newman-Keuls检验,非正态分布的数据经数据转换为正态后进行统计。P<0.05被认为有统计学意义。结果1、模型组大鼠腹主动脉SIRT1 mRNA表达较对照组明显降低,表达差异有统计学意义(P<0.05)。而二甲双胍治疗12周后SIRT1 mRNA的表达较模型组明显升高,表达差异有统计学意义(P<0.05)。2、OLETF模型组大鼠在光学显微镜下观察,可见腹主动脉内皮下间隙增宽,染色变淡,结构疏松,中膜平滑肌细胞排列紊乱。OLETF治疗组大鼠内皮下间隙轻度增厚,中膜层平滑肌细胞排列整齐。结论1、动脉中SIRT1的表达降低可能在2型糖尿病及其大血管并发症的发生发展中具有重要作用,SIRT1的表达下降可能与糖尿病大血管病变相关。2、OLETF模型组大鼠腹主动脉形态学发生改变。OLETF治疗组大鼠腹主动脉病理改变较OLETF模型组明显变轻。且二甲双胍治疗12周后,2型糖尿病大鼠腹主动脉SIRT1 mRNA的表达较模型组明显升高。因而本研究认为二甲双胍可能通过升高SIRT1 mRNA的表达而具有保护糖尿病大血管的作用。以上结果表明SIRT1可能成为糖尿病动脉粥样硬化治疗的靶点。更多还原

【Abstract】 ObjectivesType 2 diabetes mellitus is one of the major public health problems in the world, and its major complication,diabetic atherosclerosis, accounts for the leading death of diabetic patients. However, the underlying mechanism of diabetic atherosclerosis has not been fully clarified. SIRT1 is a NAD+-dependent deacetylase, which regulates life span in multiple model organisms in response to caloric restriction and has gained considerable attention for their relation with aging, diabetes mellitus, and atherosclerosis. In addition, recent studies point to SIRT1 as a key regulator of vascular homeostasis, whether SIRT1 play a role in the occurrence and development of diabetic atherosclerosis is not clear. Here, the expressions of SIRT1 in abdominal aorta of spontaneous diabetic rats were analyzed, and the effects of metformin on SIRT1 expression of abdominal aorta were also investigated.Contents1. Otsuka Long-Evans Tokushima Fatty (OLETF) rats were used. It develops diabetics spontaneously. The control is the nondiabetic Long-Evans Tokushima Otsuka (LETO) rats. The morphology and structures of abdominal aorta of the OLETF and the LETO rats were compared.2. The expression of SIRT1 in the abdominal aorta of the OLETF rats and its effects on the development of diabetic atherosclerosis were studied3. OLETF rats were fed with metformin for 12 weeks and pathological changes in the abdominal aorta and SIRT1 expression were analyzed and compared with those of the rats fed with placebo.Methods1. mRNA levels of SIRT1 in abdominal aorta of LETO and OLETF rats were assessed by real-time PCR. The morphology of abdominal aorta of each group was observed by light microscope after HE staining.2. SPSS 16.0 software was used for statistical analysis. Comparison of numerical variable data was made with the single factor analysis of variance (ANOVA). Differences among individual groups were analyzed by SNK-q test.They were considered statistically significant when P<0.05.Results1. The expression of SIRT1 mRNA in the diabetic OLETF group was significantly lower than that in the nondiabetic LETO group (P< 0.05). Metformin treatment for 12 weeks significantly increased the levels of SIRT1 expression (P<0.05).2. Observations under light microscope revealed that, the intima was smooth without eminence and the smooth vascular cells in the tunical media were lining up in order in the abdominal aorta of the LETO rats;. But in the OLETF rats, the subendothelial space was widen, with less coloration and with a more loose configuration, suggesting fat deposition. Smooth vascular cells in the tunical media of the OLETF rats were deranged, suggesting their proliferation and migration into the intima. All the abnormal manifestations observed in the OLETF rats were consistent with early signs of atherosclerosis.Conclusions1. The lower expression of SIRT1 in the diabetic group is correlated with the occurrence and development of diabetes and its macrovascular compl’ ations.2. Metformin treatment for 12 weeks greatly increased the levels of SIRT1 expression and improved atherosclerosis of the diabetic rats, which may be SIRT1-dependent.3. In conclusion, SIRT1 holds great promise as a target in the treatment of diabetic macrovascular diseases such as atherosclerosis.更多还原