黄芩甙预处理对缺血再灌注大鼠心功能和心肌细胞游离钙的影响

Effects of Baicalin Preconditioning on Cardiac Function and Intracellular Free Ca^(2+) of Ischemia Reperfusion Hearts in Rats in Vitro

目的:观察黄芩甙预处理对缺血/再灌注(I/R)大鼠离体心功能和心肌细胞游离[Ca2+]i的影响,探讨其对心脏I/R损伤的保护作用及可能机制。方法:SD大鼠50只,摘取心脏后采用Langendorff心脏灌流系统分为五组进行实验,对照组采用正常Tyrode液灌流90min;I/R组先用正常Tyrode液灌流30min后,再行I/R各30min;三种浓度(10、20、40μmol/L)黄芪甙预处理组于停止灌注前,用正常Tyrode液灌流10min后再用不同浓度黄芩甙液灌流20min,最后行I/R各30min。观察各组心功能指标冠脉流量(CF)、左室舒张末压(LVEDP)、左室发展压(LVDP)、左室收缩压最大上升/下降速率(dp/dtmax和dp/dtmin);分离单个心肌细胞,检测心肌细胞内Ca2+荧光染色强度,计算[Ca2+]i。统计学分析各组各指标测值差异及其相关性。结果:方差分析显示,心功能指标和[Ca2+]i在各组大鼠之间差异有统计学意义(P<0.01)。两两比较表明,I/R组各心功能指标明显低于对照组,[Ca2+]i高于对照组(P均<0.01);3种浓度黄芩甙预处理后,心功能指标值明显升高,[Ca2+]i明显降低(P<0.05,P<0.01)。相关性分析表明,黄芩甙预处理浓度与心功能指标变化呈正相关,与[Ca2+]i变化呈负相关(P<0.05,P<0.01)。结论:黄芩甙预处理可显著改善I/R心肌的舒缩功能,其机制可能与黄芩甙降低I/R心肌细胞内游离[Ca2+]i有关。

Objective： To observe the effects of baicalin preconditioning on cardiac function and intracellular free Ca2＋ of ischemia-reperfusion（I/R） ,and further clarify the protection and mechanism of baicalin on I/R injury in isolated rat hearts in vitro. Method： 50 SD rats were randomly divided into control group （perfused 90min by used normal Tyrode solution）, I/R group （perfused 30rain by used normal Tyrode solution, and ischemia 30min, as well as reperfusion 30min） and three dose baicalin groups （10.20.40μmol/L baicalin preconditioning 20min, and ischemia 30min, as well as reperfusion 30min） via using Langendorff-perfusion system in vitro. The values of coronary arterial flow （CF）, left ventricular diastolic end pressure （LVEDP）, left ventricular developed pressure （LVDP）, the maximum rising and dropping rates of left ventrieular pressure（dp/dt max ＆ dp/dtmin） were measured. Single rat ventricular myocytes were enzymatically dissociated for detecting fluorescence intensity of intracellular Ca2＋ to calculate [Ca2＋ ]. Difference and correlation of every testing value to obtain from 5 groups was statistically analyzed. Results： Analysis of variance was demonstrated that every observing value gaining from heart function and [Ca2＋ ]i were statistical significance between different groups in rat hearts （P〈0.01）. Comparison of both groups was indicated that parameters of cardiac performance in I/R group were significantly lowered to be compared with control group, and [Ca2＋ ]i were upward exceeding to control group （P of all 〈0.01）. With three doses baicalin preconditioning, values of cardiac performance were obviously increased, and [Ca2＋]i was severely decreased （P〈0.05, P〈0. 01）. Correlated analysis were shown that the change of heart function value was positive correlation, and [Ca2＋ ]i was negative correlation accompany to increase of concentrations of baicalin in baicalin preconditioning groups （P〈0.05, P〈0.01）. Conclusion： Baicalin preconditioning could markedly improve the diastolic and systolic functions of injured I/R hearts. It could attribute to that baicalin could decrease the Ca2＋ overloading of cardiomyocytes period I/R.