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肾素血管紧张素醛固酮系统拮抗剂对自发性高血压大鼠心肌缝隙连接蛋白Cx43表达的影响
Effect of RAAS Antagonist on the Expression of Gap Junction Cx43 in Myocardium of Spontaneously Hypertensive Rat
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摘要: 目的 探讨心肌缝隙连接蛋白Cx43在自发性高血压大鼠心肌中的表达以及肾素血管紧张素醛固酮系统(RASS)拮抗剂对其的干预机制。 方法 取8周雄性、体质量约200 g的自发性高血压大鼠(SHR)70只,随机分为高血压组、雷米普利组、替米沙坦组、依普利酮组、雷米普利+替米沙坦组、雷米普利+依普利酮组以及替米沙坦+依普利酮组,每组10只,再取同周龄、同体质量Wistar大鼠10只作为对照组。适应性喂养1周后,每天早8点给予灌胃给药,分别于0、4周及8周测量大鼠的尾动脉压,8周后处死动物,取出心脏,测量左心室质量及左心室质量/体质量,石蜡切片观察心肌纤维化程度,RT-PCR和Western blot观察Cx43的表达。 结果 喂养结束时,SHR组血压高于Wistar组(P<0.01),给予RAAS拮抗剂干预后,血压下降(P均<0.05),替米沙坦+依普利酮组血压下降最明显(P<0.01);替米沙坦+依普利酮组大鼠的左心室质量、左心室质量/体质量、心肌纤维化程度及血管紧张素Ⅱ(AngⅡ)下降也最明显(P<0.01);SHR组Cx43表达低于Wistar组(P<0.01),给予RAAS拮抗剂干预后,Cx43表达升高(均P<0.05),升高幅度仍以替米沙坦+依普利酮组最为明显(P<0.01)。 结论 高血压大鼠心肌缝隙连接蛋白Cx43表达降低,RAAS拮抗剂可以升高Cx43的表达,其中以替米沙坦与依普利酮联合效果最明显。
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关键词:
- 心肌缝隙连接蛋白Cx43 /
- 肾素血管紧张素系统 /
- 自发性高血压大鼠
Abstract: Objective To investigate the expression of gap junction protein Cx43 in the cardiac muscle of spontaneous hypertensive rat and the effects of various antagonists against renin angiotensin aldosterone system (RAAS) on Cx43 expression. Methods 70 spontaneous hypertensive rats of 8-week age, 200-gram weight were separated into 7 groups, as hypertension, ramipril, telmisartan, eplerenone, ramipril+telmisartan, telmisartan+eplerenone, and ramipril+eplerenone treatment group. Another 10 healthy Wistar rats of the same age and weight were used as control group. All the rats were given intragastric administration at 8 a.m. every morning, and measured arteria caudilis pressure at 0, 4 and 8 week, respectively. 8 weeks later, all the rats were sacrificed, and the hearts were taken to measure the weight of left ventricle and the ratio of left ventricle to body weight. Myocardial fibrosis was observed by H&E staining of paraffin embedded sections, and Cx43 expression was examined by RT-PCR and western blot. Results The arteria caudilis pressure of spontaneous hypertensive rats was significantly higher than that of healthy control Wistar rats (P<0.01). The decreased blood pressure was observed in RAAS antagonists treated rats, compared with hypertension group (P<0.05). The combined treatment of telmisartan and eplerenone had the best effect of lowering blood pressure. Moreover, the weight of left ventricle, the ratio of left ventricle to body weight, myocardial fibrosis and angiotensin Ⅱ were all prominently decreased in telmisartan and eplerenone combination group (P<0.01). The expression of Cx43 in spontaneous hypertensive rats was significantly lower than that of healthy control Wistar rats (P<0.01). Increased Cx43 expression was observed in RAAS antagonists treated rats, compared with hypertension group (P<0.05). Conclusion The expression of gap junction protein Cx43 was significantly down-regulated in spontaneous hypertensive rats, while RAAS antagonists increased Cx43 expression. The combination of telmisartan and eplerenone effectively recovered the expression of Cx43 and probably reversed hypertension. -
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