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血管紧张素转移酶2在糖尿病大鼠肾损伤发生发展中的变化

张伟, 马畅, 王艳霞, 王珊珊, 张源淑^*

南京农业大学农业部动物生理生化重点开放实验室，南京 210095

摘要

本研究通过观察糖尿病大鼠肾损伤发生发展过程中肾脏组织血管紧张素转移酶2 (angiotensin converting enzyme 2, ACE2)的表达差异，结合循环系统和肾脏组织中血管紧张素Ⅱ (angiotensin II, AngⅡ)水平的变化，探讨ACE2在高血糖致肾损伤发生发展中的作用。SD大鼠随机分为对照组和糖尿病组，腹腔内一次性注射链脲佐菌素(streptozotocin, STZ)诱导糖尿病肾损伤模型，大鼠分别在实验的第15天和30天处死。测定大鼠血糖和肾功能相关指标。利用荧光定量PCR和Western blot的方法检测肾脏ACE2的相对表达。通过放射免疫法测定血清和肾脏组织中AngⅡ含量。结果显示：(1) 注射STZ 48~72 h后大鼠开始出现多尿、多饮症状；(2) 正常对照组大鼠血糖值介于4.9~6.5 mmol/L之间；糖尿病组造模后15 d时大鼠血糖值在14.0~17.5 mmol/L之间；造模后30 d时大鼠血糖值均高于24 mmol/L；(3) 糖尿病组造模后15 d时，大鼠尿糖升高，与正常对照组相比差异显著(P < 0.05)，尿蛋白含量略高于正常对照组(P > 0.05)；而造模后30 d时大鼠的尿糖、尿蛋白含量均显著高于正常对照组(P < 0.01)；(4)与对照组相比，糖尿病组造模后15 d时大鼠肾组织中ACE2 mRNA表达升高，但差异不显著(P > 0.05)，蛋白水平显著升高(P < 0.05)；造模后30 d时ACE2 mRNA表达较对照组显著降低(P < 0.05)，蛋白表达较对照组有下降趋势(P = 0.0718)；(5)放射免疫测定结果显示，与对照组相比，糖尿病组造模后15 d时血清和肾脏组织中AngⅡ含量稍有升高，差异不显著(P > 0.05)；而造模后30 d时血清和肾脏组织中AngⅡ均显著升高(P < 0.05)。以上结果提示，ACE2在糖尿病早期肾损伤的发病机制中起到积极的保护作用。随着糖尿病肾损伤程度的逐渐加深，ACE2的表达降低导致AngⅡ的积聚，从而加重肾损伤。

关键词： 糖尿病; 肾损伤; 血管紧张素转移酶2; 表达变化; 血管紧张素Ⅱ

[Changes of angiotensin converting enzyme 2 in the occurrence and development of diabetic renal injury in rat.] [Article in Chinese]

Zhang Wei, MA Chang, WANG Yan-Xia, WANG Shan-Shan, ZHANG Yuan-Shu^*

Key Laboratory of Animal Physiology and Biochemistry, Ministry of Agriculture, Nanjing Agriculture University, Nanjing 210095, China

Abstract

This project was designed to investigate the role of angiotensin converting enzyme 2 (ACE2) in the diabetic renal injury by observing the expression of ACE2 in the kidney and the level of angiotensin II (AngII) in the circulatory system and kidney tissue of rats with diabetes. SD rats were randomly divided into control group and diabetes group. Diabetic nephropathy model was established by i.p. injection of streptozotocin (STZ). The rats were sacrificed separately on the 15th or 30th day after STZ injection. Biochemical parameters including blood glucose and renal function were examined. The expression of ACE2 in the kidney was detected by real-time PCR and Western blot. The contents of AngII in plasma and kidney were detected by radioimmunoassay. The results are as follows: (1) 48-72 h after STZ injection, the rats showed polyuria, polydipsia and their activity reduced. (2) Blood glucose levels were 4.9-6.5 mmol/L in the control rats, 14.0-17.5 mmol/L in the diabetes group rats on the 15th day, and higher than 24 mmol/L in the diabetes group rats on the 30th day; (3) There was a significant increase of urine glucose level (P < 0.05), and a slight but not significant increase of urine protein level (P > 0.05) in the diabetes group on the 15th day; On the 30th day, the levels of urine glucose and urine protein were significantly higher than those in the control group (P < 0.01); (4) Compared with the control group, the expression of ACE2 mRNA was slightly increased (P > 0.05), and the expression of ACE2 protein was significantly increased (P < 0.05) in the rats of diabetic model group on the 15th day; however, on the 30th day, ACE2 mRNA expression in the rats of diabetic model group was significantly lower than the control group (P < 0.05), and the expression of ACE2 protein was slightly lower than the control group (P = 0.0718). (5) Compared with the control group, the levels of AngII in plasma and kidney of the diabetic rats increased slightly on the 15th day (P > 0.05); while the AngII levels in diabetic model group rats were significantly higher (P < 0.05) than that in control rats on the 30th day. These results suggest that ACE2 plays a positive role in the protection against the pathogenesis of early renal damage. ACE2 expression is reduced gradually with the deepened degree of diabetic kidney damage, leading to the accumulation of AngII in the kidney, thereby increasing the renal injury.

Key words: Diabetes; renal injury; angiotensin converting enzyme 2; change of expression; angiotensin II

收稿日期：2012-12-10　　录用日期：2012-12-31

通讯作者：张源淑　　E-mail: zhangyuanshu@njau.edu.cn

引用本文：

张伟, 马畅, 王艳霞, 王珊珊, 张源淑. 血管紧张素转移酶2在糖尿病大鼠肾损伤发生发展中的变化[J]. 生理学报 2013; 65 (4): 402-408.

Zhang Wei, MA Chang, WANG Yan-Xia, WANG Shan-Shan, ZHANG Yuan-Shu. [Changes of angiotensin converting enzyme 2 in the occurrence and development of diabetic renal injury in rat.] [Article in Chinese]. Acta Physiol Sin 2013; 65 (4): 402-408 (in Chinese with English abstract).