哇巴因对血管紧张素Ⅱ及其1型和2型受体mRNA在心肌中表达的影响

The expression of angiotensin Ⅱ and its subtype 1 and 2 receptors in the myocardium of ouabain-induced hypertensive rats

目的观察哇巴因(Ouabain)对血管紧张素Ⅱ(AngⅡ)及其1型(AT1)与2型(AT2)受体mRNA在心肌中表达的影响。方法60只SD大鼠随机分为3组,分别为Ouabain组[27.8 ng/(kg.d)Ouabain腹腔注射]、Losartan组[27.8 ng/(kg.d)Ouabain腹腔注射,同时给予Losartan 30 ng/(kg.d)灌胃]、对照组(生理盐水2 mL/d腹腔注射),每周测定鼠尾血压,共6周。应用放免法测定各组大鼠血浆及心肌中AngⅡ质量浓度,同时采用实时定量荧光PCR(FQ-PCR)观察心肌中AT1和AT2mRNA表达的变化。结果血浆中的AngⅡ质量浓度在Ouabain组及Losartan组均显著高于对照组(P<0.05),而Ouabain组心肌中AngⅡ质量浓度无明显变化。与对照组相比,Ouabain组及Losartan组心肌中AT1mRNA与AT2mRNA的表达明显上调(P<0.05)。结论外周长期、慢性给予Ouabain后可持续升高SD大鼠的血压,并使RAS系统激活,这一作用可能是通过AT1受体介导。给予Ouabain激活AT1受体的同时,AT2活性也增加。

Objective To receptors in the myocardium of investigate how ouabain influence angiotensin Ⅱ（Ang Ⅱ ） and its subtype 1 and 2 ouabain-induced hypertensive rats. Methods 60 Sprague-Dawly （SD） rats were randomly divided into three groups： two experimental groups and a control group. One of the experimental groups was injected with 27.8 ng/（kg · d） ouabain intraperitoneally, the other was injected with 27.8 ng/（kg· d） ouabain and losartan 30 ng/（kg ·d）. The control group was given placebo. Then, the blood pressure （BP） were measured every week and all rats were killed 6 weeks later. Radioimmunity and FQ-PCR were used to observe the changes of Ang Ⅱ and its subtype 1 and 2 receptors in the myocardium of these ouabain-induced hypertension rats. Results Plasma Ang Ⅱ of the ouabain-induced hypertension group was higher than that of the control group （ P〈0.05）, but these was no change in the myocardium Ang Ⅱ . AT1 rnRNA and AT2 mRNA in the ouabain-induced hypertension group was remarkablely higher than that in the control group （P〈0.05）. Conclusion A long-term and peripheral administration of ouabain can raise blood pressure of rats, which may be induced by AT1 receptor. Ouabain can activate AT1 receptor as well as AT2 receptor.