降压药物干预高盐饮食复合冷应激诱导大鼠的心肌肥厚

Effects of antihypertensive agent on cardiac hypertrophy in hypertensive rats induced by high salt diet combined with cold stress

目的 研究药物干预对高盐复合冷应激诱导大鼠的肾素 血管紧张素 醛固酮系统、血压和心肌肥厚的影响。方法 Wistar大鼠随机分为 5组 :正常对照组 ,未治疗组 ,卡托普利组 ,倍他乐克组和尼群地平组。除正常对照组外 ,其余 4组大鼠在药物或生理盐水干预的同时 ,均给予含 8%NaCl饲料喂养 ,并每天置于 5± 2℃冷室内 4h。每周测血压和体质量一次 ,8周后处死动物称全心脏湿质量。用放免法测定大鼠左室心肌肾素活性、血管紧张素Ⅱ和醛固酮浓度。结果 ①倍他乐克组大鼠左室心肌肾素活性、血管紧张素Ⅱ和醛固酮浓度明显低于未治疗组、卡托普利组和尼群地平组 (P <0 .0 1) ,与对照组无明显差异。② 3种药物干预的大鼠血压均明显低于未治疗组 (P <0 .0 1) ,与对照组之间无差异。③尼群地平组大鼠心脏质量指数与对照组之间无显著性差异 ,但显著低于卡托普利组和倍他乐克组 (P <0 .0 1)。结论 尼群地平可抑制大鼠心肌肥厚 ,卡托普利和倍他乐克则无此作用 。

Objective To observe the effects of antihypertensive agents on renin angiotensin aldosterone system, blood pressure and myocardial hypertrophy induced by high salt diet plus cold stress. Methods Fifty male Wistar rats weighting 200～250 g were divided into 5 groups: control, saline, captopril, betaloc and nitrendipine. The rats treated with dugs or saline were fed with high salt diet(8% NaCl) and subjected to cold stress 4 hours a day. Blood pressure and body weight were measured once a week. Rats were sacrificed and then the gross weight of hearts was measured 8 weeks later. Renin activity(RA), angiotensinⅡ(AngⅡ) and aldosterone(Aldo) in the left ventricular wall were determined by radioimmunoassay. Results ① Levels of RA, AngⅡ and Aldo of rat left ventricular wall in betaloc group were significantly lower than those in saline, captopril and nitrendipine groups( P <0.01). ② After administration of captopril, betaloc and nitrendipine, systolic blood pressure in these three groups was significantly lower than that in saline and control groups( P <0.01). ③ Rat heart mass index in nitrendipine group was significantly lower than that in captopril and betaloc groups( P <0.01). Conclusion Nitrendipine, but not captopril or betaloc, can improve rat cardiac hypertrophy induced by high salt diets plus cold stress, indicating that calcium may play an important role in cardiac hypertrophy of this unique hypertensive animal model.