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目的:观察血管紧张素转化酶2(ACE2)在自发性高血压大鼠(SHR)血管中的表达以及缬沙坦对ACE2mRNA表达的影响。方法:24只12周龄雄性SHR随机分为SHR组和缬沙坦组,每组各12只,另设12只同龄雄性血压正常的Wistar大鼠作为对照组。缬沙坦组大鼠给予缬沙坦30mg.kg-1.d-1灌胃,SHR组及对照组给予等量0.9%氯化钠溶液灌胃。10周后,截取胸主动脉,光镜观察血管的病理变化,测定中膜厚度与血管腔内径之比;采用RT-PCR和免疫组织化学法检测胸主动脉中ACE2的表达。结果:与对照组比较,SHR组血管壁明显增厚,管腔变窄,且血管中ACE2mRNA和蛋白的表达均下调;而缬沙坦组ACE2mRNA和蛋白的表达明显高于SHR组。结论:高血压时血管重构可能与ACE2的表达下调有关,缬沙坦可能通过增加血管中ACE2的表达而发挥保护血管的作用。
Objective: To observe the expression of angiotensin converting enzyme 2 (ACE2) in blood vessels of spontaneously hypertensive rats (SHR) and the effect of valsartan on the expression of ACE2 mRNA. Methods: Twenty-four male SHRs at 12 weeks of age were randomly divided into SHR group and valsartan group, with 12 rats in each group. Twelve male Wistar rats of same age were used as control group. Valsartan group rats were given valsartan 30mg.kg-1.d-1 gavage, SHR group and control group were given 0.9% sodium chloride solution gavage. After 10 weeks, the thoracic aorta was intercepted and the pathological changes of the blood vessels were observed with light microscope. The ratio of the media thickness to the intraluminal diameter was determined. The expression of ACE2 in the thoracic aorta was detected by RT-PCR and immunohistochemistry. Results: Compared with the control group, the vessel wall in SHR group was significantly thicker and the lumen was narrowed, and the expression of ACE2 mRNA and protein in blood vessels was down-regulated. The expression of ACE2 mRNA and protein in valsartan group was significantly higher than that in SHR group. Conclusion: Vascular remodeling may be related to the down-regulation of ACE2 expression in patients with hypertension. Valsartan may protect the blood vessels by increasing the expression of ACE2 in blood vessels.