血管紧张素1-7与糖尿病及糖尿病肾脏内质网应激关系的研究

Relationship between angiotensin 1-7, diabetes and endoplasmic reticulum stress of diabetic kidney

目的调查糖尿病患者血管紧张素1—7（Angl-7）水平和评价Angl-7对糖尿病大鼠肾脏内质网应激的影响。方法选取2014年12月至2015年6月于天津市海滨人民医院未诊断为糖尿病的95名体检人员为研究对象，所有受试者均进行口服葡萄糖耐量试验，根据血糖水平分为健康组（n=31）、血糖异常组（n=32）和糖尿病组（n=32）。检测其体重、腰围、血压、肝功能、肾功能、Angl-7、血管紧张素转换酶（ACE）2等指标。分析血糖与Angl-7、ACE2的相关性。另外，选取10只150～200g健康雄性Sprague—Dawley（SD）大鼠，通过腹腔注射链脲佐菌素制备糖尿病模型，全部成功，根据随机数字法，分为糖尿病组和Angl-7组，每组5只，分别皮下泵人生理盐水和Angl-7，另选取5只健康SD大鼠作为正常组。干预2周后处死所有大鼠，留取肾组织标本，Western61~迹和实时荧光定量PCR检测葡萄糖调节蛋白78（GRP78）、转录活性因子4（ATF4）、增强子结合蛋白同源蛋白（CHOP）水平。结果与健康组相比，血糖异常组和糖尿病组甘油三酯、ACE2、Angl-7水平均升高；糖尿病组较健康组升高更明显（F=5．57，6．12，5．44，P均〈0．01）。Pearson相关分析显示，糖尿病组、血糖异常组的空腹血糖、餐后血糖均与Angl-7呈正相关（r=0．69，0．45，P均〈0．01；r=0．54，0．52，P均〈0．01）。与正常组相比，糖尿病组大鼠肾脏GRP78、ATF4和CHOP水平明显升高；与糖尿病组相比，Angl-7组GRP78、ATF4和CHOP水平明显下降（t=20．3，25．7，19．6，P均〈0．05）。与同期正常组比较，糖尿病组大鼠肾组织GRP78、ATF4和CHOP的mRNA均显著上调。与糖尿病组比较，Angl-7组大鼠肾组织GRP78、ATF4和CHOP的mRNA的表达受到显著抑制（t=15．1，11．6，12．3，P均〈0．05）。结论Angl-7水平随着受试者血糖浓度的升高而升高，另外，Angl-7可降低糖尿病大鼠肾脏内质网应激蛋白水平。

Objective To investigate the level of angiotensin 1-7 （Angl-7） in patients with diabe- tes, and to study the effects of Angl-7 on endoplasmic reticulum （ER） stress in the kidney of diabetic rats. Methods Ninety-five subjects without diagnosed diabetes were screened in Tianjin Seaside People＇s Hospi- tal from December 2014 to June 2015. Oral glucose tolerance test was implemented. According to the level of blood glucose, subjects were divided into three groups： healthy group （n = 31 ）, impaired glucose group （ n = 32）, and diabetes group （n = 32）. Body weight, waist circumference, blood pressure, liver function, renal function, Angl ＂7, angiotensin-converting enzyme （ACE）2 and other indicators were detected. Rela- tionship between blood glucose and Angl-7 and ACE2 were analyzed. In addition, ten healthy male Sprague- Dawley （SD） rats （ 150-200 g） were chosen to induce diabetes through intraperitoneal injection of streptozo- tocin, and all succeeded. Ten diabetic rats were randomly divided into Angl-7 group and diabetes group aecording to the random number method, and pumped into Angl-7 or saline solution, respectively, with five rats in each group. Other five healthy SD rats were chosen as normal group. All rats were sacrificed after in- tervention for two weeks. Kidney specimens were used to test the level of ER stress proteins, including glu- cose-regulated protein（GRP） 78, activity of transcription factor （ATF）4, enhancer binding protein homolo- gous protein （CHOP）, by Western Blotting and Real-time Quantitative PCR. Results Compared with healthy group, levels of triglycerides, ACE2, Angl-7 in impaired glucose group and diabetes group were in- creased,especially the diabetes group （ F = 5.57,6.12,5.44, all P 〈 0.01 ）. Pearson correlation analysis showed that fasting blood glucose and postprandial blood glucose in diabetes group and impaired glucose group were positive correlated with Ang1-7 （ r = 0.69,0.45, all P 〈 0.01 ; r = 0.54,0.52, all P 〈 0.01 ）. Compared with normal group, levels of GRP78, ATF4, and CHOP were increased significantly in diabetes group; compared with diabetes group, levels of GRP78, ATF4, and CHOP were significantly reduced in Angl-7 group（t =20.3, 25.7, 19.6, all P 〈0.05）. Compared with normal group, mRNA levels of GRP78, ATF4, and CHOP were increased significantly in diabetes group; compared with diabetes group, levels of GRP78, ATF4, and CHOP were significantly reduced in Angl-7 group （t = 15.1, 11.6, 12.3, all P 〈 0.05 ）. Conclusions The level of Angl-7 evelates with the increase of blood glucose concentration in subjects. Angl-7 reduces ER stress in the kidney of diabetic rats.