大蒜素对血管紧张素Ⅱ诱发人心房肌细胞钙电流和游离钙离子浓度的影响

背景近年来发现血管紧张素Ⅱ可诱发心房电重构,而大蒜素具有相应的拮抗作用,可阻止或减轻心房电重构的发生.目的观察大蒜素对血管紧张素Ⅱ诱发人心房肌细胞膜钙通道电流和细胞内游离钙离子浓度的影响.设计以急性分离的人的心房肌细胞为实验对象,随机对照设计.单位一所军医大学医院心内科.方法实验于2003-06/2004-06在第四军医大学西京医院心脏内科实验室完成.选择在此期间接受心脏体外循环手术的先天性心脏病患者10例;男6例,女4例,平均年龄(15±6)岁.术中取患者右心耳标本送至实验室后,急性分离单个人心房肌细胞,实验分4组对照组(不加任何干预措施);血管紧张素Ⅱ组加入终浓度为0.1μmol/L的血管紧张素Ⅱ;大蒜素组加入终浓度为50μmol/L的大蒜素;血管紧张素Ⅱ+大蒜素组大蒜素50 μmol/L与血管紧张素Ⅱ0.1μmol/L同时加入.采用全细胞膜片钳方法记录L型钙电流;以钙荧光探针荧光指示剂负载,应用激光共聚焦显微镜技术,分别于加入干预药物后即刻与15min检测游离钙离子浓度变化.主要观察指标各组人心房肌细胞L型钙电流峰值电流密度及钙离子游离钙离子的荧光强度变化率.结果①血管紧张素Ⅱ组人心房肌细胞膜L型钙电流峰值电流密度明显高于对照组[(-12.77±1.61),(-5.78±0.81)pA/pF,P＜0.05).②大蒜素组人心房肌细胞膜L型钙电流峰值电流密度与对照组比较,无明显差异[(-5.69±0.83)pA/pF,P＞0.05].③血管紧张素Ⅱ+大蒜素组人心房肌细胞膜L型钙电流峰值电流密度明显低于血管紧张素Ⅱ组[(-8.75±0.97)pA/pF,P＜0.05).④血管紧张素Ⅱ组人心房肌细胞内游离钙离子荧光强度和游离钙离子荧光强度变化率明显高于对照组和大蒜素组[(2610.1±112.6,(299.2±27.3)%;653.9±42.5,0;639.5±44.7,(-2.2±0.6)%,P＜0.05].血管紧张素Ⅱ+大蒜素组人心房肌细胞游离钙离子荧光强度和游离钙离子荧光强度变化率明显低于血管紧张素Ⅱ组[(1284.9±85.2,(96.5±8.4)%,P＜0.05].结论大蒜素可拮抗血管紧张素Ⅱ致人心房肌细胞膜L型钙电流峰值电流密度的增加,拮抗人心房肌细胞内钙超载,产生减轻心房肌细胞电重构的作用.

Effects of allicin on angiotensin Ⅱ-induced calcium current and intracellular free calcium concentration in human atrial myocytes

BACKGROUND: Angiotensin Ⅱ has been found to induce atrial electrical remodeling, which can be blocked or inhibited by allicin.OBJECTIVE: To study the effects of allicin on angiotensin Ⅱ-induced calcium channel current and intracellular free calcium concentration in human atrial myocytes.DESIGN: A randomized controlled study based on human atrial myocytes freshly isolated.SETTING: Cardiology department of a military medical university of Chinese PLA.METHODS: This study was carried out from June 2003 to June 2004 in the Laboratory of Cardiology Department, Xijing Hospital, the Fourth Military Medical University of Chinese PLA. Ten patients with congenital heart disease who underwent extracorporeal circulation surgery were included in the study. Among them, there were 6 males and 4 females with the average age of 15 ± 6 years. Tissue samples were taken from their right auricle and sent to the lab, where the atrial myocytes were freshly isolated. There were four co-administration of angiotensin Ⅱ (0. 1 μmol/L)and allicin(50 μmol/L).The conventional whole-cell configuration of the patch-clamp technique was used to detect membrane electric current of Ca2 + in L type. Confocal microscope was used with Fluo-3/AM as calcium indicator to detect changes of intracellular free calcium concentration immediately and 15 minutes after drug intervention, respectively.MAIN OUTCOME MEASURES: The peak density of electric current of Ca2 + in L type and alteration of fluoresence intensity of intracellular free calcium concentration.electric current of Ca2 + in L type in human atrial myocytes was significantly increased by angiotensin Ⅱ of 0. 1 μmol/L[( - 12. 77 ± 1. 61) vs ( -5.78affect electric current of Ca2+ in L type in human atrial myocytes group, the peak density of electric current of Ca2 + in L type was significantly lower than that in angiotensin Ⅱ group[ ( - 8.75 ± 0.97) pA/pF, P ＜ 0. 05 ].in angiotensin Ⅱ group was significantly higher than that in control and allicin groups[(2 610.1±112.6, (299.2±27.3)%; 653.9±42.5, 0;simultaneously with angiotensin Ⅱ, the alteration of intracellular fluoresence intensity was much lower than that in angiotensin Ⅱ group[ ( 1284.9 ± 85.2,(96.5±8.4)%;P ＜0.05].CONCLUSION: Allicin antagonizes angiotensin Ⅱ-induced increase in the peak density of electric current of Ca2+ in L type and intracellular calcium overload, which may relieve atrial electrical remodeling.