肥胖与非肥胖2型糖尿病大鼠血管内皮依赖性舒张功能变化及高糖／高渗透压机制  

Changes of endothelium-dependent vasodilation in aortae from obese and non-obese type 2 diabetic rats and the roles of hyperglycemia/hyperosmolarity

作　　者：陈浥尘 杜舟[1] 钟梅芳 杨洁[1] 滕林[1] 中村恭子 田渕正樹 东野英明 顾坚忠[3] 陈红[1] 

机构地区：[1]上海交通大学医学院药理学教研室,200025 [2]日本近畿大学医学部药理学教研室 [3]中国科学院上海实验动物中心

出　　处：《中华高血压杂志》2011年第6期529-537,共9页Chinese Journal of Hypertension

基　　金：国家自然基金项目(30971154及30770848);上海市卫生局基金(2007167)

摘　　要：背景高血糖以及严格降糖治疗对2型糖尿病患者心血管功能损害与预后的影响存在很大争议。目的本实验对照研究肥胖与非肥胖糖尿病大鼠血管内皮依赖性舒张功能,研究胰岛素治疗对血管舒张功能的影响以及内皮型一氧化氮合酶/血红素加氧酶(endothelial nitric oxide synthase,eNOS/heme oxygenate,HO)相关的高糖/高渗透压机制。方法 采用24周龄2型糖尿病Otsuka Long-Evans Tokushi ma Fatty(OLETF)大鼠与Goto-Kakizaki(GK)大鼠,测定离体胸主动脉血管舒张功能,免疫荧光法检测血管eNOS/HO。②另一组GK大鼠注射胰岛素连续10d降糖治疗后,观察主动脉舒张功能及内膜超微结构。③主动脉以高糖缓冲液(正常缓冲液+50mmol/L葡萄糖)及高渗缓冲液(正常缓冲液+50mmol/L甘露醇)孵育5h后,以Western Blotting法检测血管eNOS/HO含量。结果 两种糖尿病大鼠血糖均明显升高,其中以GK大鼠血糖升高最为明显[GK(15.6±2.5)比OLETF(9.9±0.4)mmol/L,P<0.01]。OLETF大鼠胰岛素水平较GK明显增高[OLETF(11.5±1.2)比GK(2.1±0.2)μg/L,P<0.01]。②OLETF主动脉内皮依赖性舒张明显减弱、eNOS减少,阻断eNOS可完全阻断OLETF内皮依赖性舒张;GK主动脉内皮依赖性舒张明显增强、血管eNOS/HO明显增加,联合阻断eNOS/HO方可完全阻断GK内皮依赖性舒张。③胰岛素注射使GK血管eNOS/HO水平明显下降、内皮依赖性舒张反应减弱,伴有内膜明显增殖。④高糖及高渗刺激可诱导血管eNOS/HO上调。结论 OLETF大鼠呈明显高胰岛素血症、主动脉内皮依赖性舒张功能降低伴eNOS减少;GK大鼠内皮依赖性舒张增强伴eNOS/HO上调,胰岛素注射减弱GK血管舒张功能并促进内膜增殖。高糖/高渗诱导血管eNOS/HO增加可能参与血管内皮功能的调节。Background There are considerable controversies over the adverse effects of hyperglycemia and tight glucose control on cardiovascular outcomes in type 2 diabetes patients. Objective This study compared aortic endothelium-dependent vasodilation between obese type 2 diabetic Otsuka Long-Evans Tokushima Fatty （OLETF） rats and non-obese diabetic Goto-Kakizaki （GK） rats. The roles of insulin in endothelium-dependent vasodilation, as well as the mechanism of hyperglycemia/hyperosmolarity in relation to endothelial nitric oxide synthase （eNOS）/ heme oxygenase （HO） , was examined. Methods②The thoracic aortae from both OLETF and GK rats of 24 weeks were isolated and vasodilatory function was assessed in vitro. Segments of the aortae were used for eNOS/ HO determination with immunofluoreseence. ② One group of GK rats were injected with insulin for 10 d before observing vasodilatory function and ultrastrueture of the intima.③Normal aortic segments were incubated in the buffer of hyperglycemia or hyperosmolarity （ by adding 50 mmol/L glucose or mannitol to Krebs-Henseleit buffer, 350 mOsm/L） for 5 h and contents of eNOS/HO were examined with Western blotting. Results ① Compared with non-diabetic controls, blood glucose levels of both OLETF and GK rats were gnificantly elevated, with the level of GK rats higher than that of OLETF rats [-GK （15.6±2.5） mmol/L vs OLETF （9.9±0.4） mmol/L,P〈0. 013. Serum insulin level in OLETF rats was higher than that of GK rats]-OLETF （11.5±1.2） vs C-K （2. 1±0.2）μg/L, P〈0. 013. ② While OLETF rats＇ aortae showed significantly reduced endothelium-dependent vasodilation with decreased eNOS level, GK had enhanced vasodilation with increased eNOS and HO. The endothelium-dependent vasodilation in OLETF could be blocked completely by the inhibition of eNOS, while concomitant blockade of eNOS and HO was indispensable for complete inhibition of endothelium-dependent vasodilation in GK rats. ③ Insulin admin istration for GK rats induced dramatic in

关 键 词：2型糖尿病 内皮依赖性血管舒张 一氧化氮合酶 血红素加氧酶 高糖/高渗透压 胰岛素 肥胖Otsuka Long—Evans Tokushima Fatty大鼠 非肥胖G-oto—Kakizaki大鼠 

分 类 号：R587.1[医药卫生—内分泌] R589.2[医药卫生—内科学]