ACE2基因敲除小鼠止血带休克后肾组织ACE/AngⅡ表达的变化及其与肾损伤的关系

Renal expression of ACE/AngⅡ in ACE2knockout mice after tourniquet shock and its relationship with renal injury

目的:通过观察血管紧张素转换酶2(ACE2)基因敲除(KO)小鼠止血带休克(TS)后肾组织血管紧张素转化酶/血管紧张素Ⅱ(ACE/AngⅡ)的表达及损伤程度的变化,探讨ACE2在休克后急性肾损伤中的作用。方法:小鼠双下肢用止血带结扎缺血2 h、松带后再灌注4 h复制TS模型。将雄性6月龄野生型(WT)C57BL/6小鼠和相同背景的ACE2 KO小鼠各12只分为4组,即WT组、WT+TS组、KO组和KO+TS组,每组6只。Westernblotting测肾组织ACE蛋白的表达;ELISA法测定肾组织AngⅡ表达;利用化学比色方法测定肾组织丙二醛(MDA)含量、超氧化物歧化酶(SOD)活性、血尿素氮(BUN)和血清肌酐(Cr)含量。结果:与WT小鼠相比,WT+TS小鼠肾组织ACE/AngⅡ表达明显增加,出现肾组织氧化应激损伤和功能改变;与WT小鼠相比,KO小鼠肾组织ACE/AngⅡ表达增加,但未见明显的氧化应激损伤和功能变化;与WT+TS小鼠相比,KO+TS小鼠肾ACE/AngⅡ表达进一步增加,肾组织氧化应激和肾功能损伤明显加重。结论:ACE2基因缺失可能通过增加ACE/AngⅡ表达加重止血带休克肾的氧化应激损伤,针对ACE2靶f点的药物有可能成为防治止血带休克时急性肾损伤的策略之一。

AIM： To investigate the effect of angiotensin-converting enzyme 2 （ACE2） on tourniquet shock （TS）-induced acute renal injury by observing the renal expression of angiotensin-converting enzyme/angiotensin Ⅱ （ACE/ AnⅡ ） and injury severity in ACE2 knockout （KO） mice. METHODS： The TS animal model was produced by bilateral tourniquet ligation in the inguinal region on both hind legs for 2 h to induce ischemia, and reperfusion was initiated by cut- ting latex rings for 4 h. Six-month-old male wild-type （WT） and ACE2 KO C57BL/6 mice were selected, and divided into 4 groups （6 mice in each group） including WT group, WT＋TS group, KO group and KO ＋TS group. The expression of ACE and Ang Ⅱ in the renal tissues was determined by Western blotting and ELISA, respectively. The renal content of ma- londialdehyde （MDA） and activity of superoxide dismutase （SOD）, blood urea nitrogen （BUN） and serum creatinine （Cr） were measured by chemical eolorimetry. RESULTS： Compared with WT group, the expression of ACE/Ang II was obviously increased in WT ＋ TS group, and significant renal oxidative stress injury was also observed. The expression of ACE/AngⅡ was elevated in KO mice, but no significant renal oxidative stress injury was found. Compared with WT ＋ TS group, more highly increased expression of ACE/Ang Ⅱ and more aggravated renal injury were exhibited in KO ＋ TS group. CONCLUSION： Deletion of ACE2 gene exacerbates TS-induced renal oxidative stress injury by increasing local ACE/Ang Ⅱ expression. The agonist targeting to ACE2 may be helpful for prevention and treatment of TS-induced acute renal injury.