川芎嗪对离体大鼠心肌在钙反常损伤时发生早期后除极的抑制作用

Inhibitory effects of tetramethylpyrazine on early afterdepolarizations induced by calcium paradox injury in myocardium of rats ex vivo

目的:观察川芎嗪对心肌细胞在缺钙-复钙损伤时发生的早期后除极及触发性心律失常的防治作用。方法:实验于2003-03/04在承德医学院中心实验室完成。Wistar大鼠,雌雄不拘,四五月龄,体质量200～250g。川芎嗪为人工合成的四甲基吡嗪注射液,北京第四制药厂产品。标本制备:81只Wistar大鼠拉颈致死后迅速取出心脏,在右心房和上腔静脉之间,用手术剪制作6mm×4mm×3mm的窦房结-右心房标本,置于浴槽内,用(37±0.1)℃并充以混合气体体积分数0.095O2、体积分数0.05CO2的Tyrode液灌流。每例标本用正常Tyrode液预灌20min,待获得稳定的动作电位波形后随机分为5组:①空白对照组(n=28):自始至终以标准Tyrode液灌流100min。②对照组Ⅰ(n=23):在用无钙Tyrode液灌流20min后,再换以标准Tyrode液(正常钙)灌流60min;③对照组Ⅱ(n=10):在用无钙Tyrode液灌流20min后,再换以含高钙(2倍正常钙浓度)Tyrode液灌流60min。④实验组Ⅰ(n=10):在用无钙Tyrode灌流20min后,用含川芎嗪(100mmol/L)的标准Tyrode液灌流60min。⑤实验组Ⅱ(n=10):在用无钙Tyrode灌流20min后,用含川芎嗪(100mmol/L)的高钙(2倍正常钙浓度)Tyrode液灌流60min。本实验采用完全随机设计,为增加对照组数据的精确性,而增加了对照组的样本数量。采用细胞内微电极技术记录离体大鼠窦房结-心房肌细胞自发动作电位,观察异常触发活动的发生情况,以及川芎嗪对触发性心律失常的防治作用。结果:81只大鼠均进入结果分析。各组间早期后除极的发生率比较:与空白对照组比较,除实验组Ⅰ与空白对照组的差异无显著性外,其余各组与空白对照组的差异均显著(7%,87%,100%,70%,P<0.005);对照组Ⅱ与对照组Ⅰ比较,差异不显著(P>0.05);实验组Ⅱ、对照组Ⅰ分别与实验组Ⅰ比较,差异显著(70%,87%,10%,P<0.005);实验组Ⅱ与对照组Ⅱ比较,差异显著(70%,100%,P<0.005)。结论:川芎嗪对早期后除极抑制作用的可能机制与其钙拮抗作用有关。

AIM： To observe the preventive and therapeutic effects of tetramethylpyrazine （TMP） on early afterdepolarizations （EAD） and triggered arrhythmias induced by calcium deficiency-recalcification injury. METHODS： The experiments were carried out between March and April 2003 at the Central Laboratory of Chengde Medical College. The Wistar rats, of either sex, aged from 4 to 5 months, with the body mass of 200-250 g, were selected. TMP was artificial injection, which was manufacture by the Fourth Pharmaceutical Factory in Beijing. Essay preparation： Totally 81 rats were killed by drawing on the neck, which hart was quickly dislodged. A specimen （6 mm×4 mm×3 mm） from sinus node-atrium muscles of rats was cut by surgical scissors between right atrium and superior vena cava, which then was put in the bath device, was perfused at a constant flow with the Tyrode solution containing mixed gas （0.095 volume fraction O2, 0.05 volume fraction CO2） by a large reservoir at （37±0.1）℃. The isolated sinus node-atrium muscles of rats were perfused for 20 minutes with normal Tyrode. The specimens were divided into 5 groups after intracellular recording were obtained stabilized： ① blank control group （n=28）： It was being re-perfused for 100 minutes with normal Tyrode from the beginning to the end; ②control group Ⅰ （n=23）： It was being re-perfused for 60 minutes with normal Tyrode （normal calcium）after being perfused for 20 minutes with Ca-free perfusate; ③control group Ⅱ （n=10） ： It was being re-perfused for 60 minutes with Ca-rich Tyrode（twice of the normal concentration）after being perfused for 20 minutes with Cafree Tyrode; ④experimental group Ⅰ （n=10） ：It was being re-perfused for 60 minutes with contain TMP （100 mmol/L） in Ca-free Tyrode after being perfused for 20 minutes with Ca-free Tyrode; ⑤experimental group Ⅱ （n=10） ： It was being re-perfused for 60 minutes with contain TMP （ 100 mmol/L）in Ca-rich Tyrode after being perfused for 20 minutes with Ca-free Tyrode. Trabant design was applied in this experiment. The number of samples of control groups was added so as to raise the truth of data, The spontaneous electric activity of sinus node-atrial muscle cell of isolated rats was recorded with intracellular microelectrode. The occurrence of triggered activity and the preventive and therapeutic effect of TMP on triggered arrhythmia were observed. RESULTS： A total of 81 rats were involved in the result analysis. Comparison of incidence rate of EAD in each group： Compared with the blank control group, there was significant difference except with the experimental group Ⅰ （7%,87%, 100% ,70%,P〈0.005） There was insignificant difference between the control group Ⅱ and control group Ⅰ （P 〉0.05）. There was significant difference between experimental group Ⅱ and experimental group Ⅰ as well as between the control group Ⅰ and experimental group Ⅰ （70%,87%, 10%, P 〈 0.005）. There was significant difference between the experimental group Ⅱ and control group Ⅱ （70%, 100%, P〈 0.005）. CONCLUSION： The possible mechanism of inhibitory effect of TMP on EAD is associated with calcium antagonism.