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

摘要

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 30min 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 ischemi-a 30min,as well as reperfusion 30min)via using Langendorff-perfusion system in vitro.The values of coronary ar-terial flow(CF),left ventricular diastolic end pressure(LVEDP),left ventricular developed pressure(LVDP),the maximum rising and dropping rates of left ventricular pressure(dp/dtmax & dp/dtmin )were measured.Single rat ventricular myocytes were enzymatically dissociated for detecting fluorescence intensity of intracellular Ca2+ to calculate [Ca2+ ]i .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 sta-tistical 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,val-ues 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.%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。