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目的观察薯蓣皂苷(dioscin,Dio)对大鼠心肌收缩力的影响。方法采用Langendorff逆行主动脉灌流法对大鼠离体心脏进行灌流,利用压力感受器插管法测定左心室相关心功能参数,记录低、中和高3个浓度Dio对左心室收缩压(LVSP)、左心室舒张末期压(LVEDP)、左心室内压最大上升/下降速率(±dp/dt_(max))的影响。利用激光共聚焦显微镜观察Dio对H9c2细胞内Ca~(2+)浓度的影响,并利用多功能酶标仪观察药物对细胞线粒体膜电位的影响。结果 0.1、1μmol·L~(-1)Dio可明显增加LVSP,由(11.55±0.52)、(10.53±0.28)kPa分别增加至(13.08±0.72)、(12.53±0.64)kPa(P<0.01);增加+dp/dt_(max)由(0.38±0.10)、(0.40±0.07)kPa·ms~(-1)分别增加至(0.42±0.11)、(0.43±0.02)kPa·ms~(-1)(P<0.05)。10μmol·L~(-1)Dio则使LVSP由(12.13±0.33)kPa减至(9.46±0.77)kPa(P<0.01),使+dp/dt_(max)由(0.42±0.04)kPa·ms~(-1)降为(0.24±0.04)kPa·ms~(-1)(P<0.01)。0.1、1、10μmol·L~(-1)的Dio可使H9c2细胞中Ca~(2+)相对荧光强度由(16.62±0.89)分别增加至(21.48±0.80)、(25.68±0.69)和(19.84±0.66)(P<0.01)。0.1、1μmol·L~(-1)Dio对H9c2细胞线粒体膜电位无明显影响,而10μmol·L~(-1)Dio会使JC-1单体与聚合物的比值由(1.14±0.03)增加为(1.35±0.06)(P<0.01),即引起线粒体膜电位下降。结论低、中浓度Dio可增加LVSP和+dp/dt_(max),表现正性肌力作用,机制为增加细胞内Ca~(2+)浓度。并且,其在增加细胞内Ca~(2+)浓度的同时并不会引起钙超载,仅高浓度出现。
Objective To observe the effect of dioscin (Dio) on myocardial contractility in rats. Methods Langendorff retrograde aortic perfusion was used to perfuse the isolated rat heart. Left ventricular related cardiac function parameters were measured by baroreceptor cannula. Left ventricular systolic pressure (LVSP), left ventricular systolic pressure Left ventricular end-diastolic pressure (LVEDP) and left ventricular pressure (± dp / dt max). The effect of Dio on intracellular Ca 2+ concentration in H9c2 cells was observed by laser confocal microscopy. The effects of drugs on mitochondrial membrane potential were observed by multi-functional microplate reader. Results DIO at 0.1 and 1 μmol·L -1 increased LVSP significantly from (11.55 ± 0.52) and (10.53 ± 0.28) kPa to (13.08 ± 0.72) and (12.53 ± 0.64) kPa (P <0.01) ; The increase of + dp / dt max increased from (0.38 ± 0.10) and (0.40 ± 0.07) kPa · ms -1 to 0.42 ± 0.11 and 0.43 ± 0.02 kPa · ms -1 ) (P <0.05). Dio at 10 μmol·L -1 reduced LVSP from (12.13 ± 0.33) kPa to (9.46 ± 0.77) kPa (P <0.01), and increased the + dp / dt max from (0.42 ± 0.04) kPa · ms ~ (-1) to (0.24 ± 0.04) kPa · ms ~ (-1) (P <0.01). The relative fluorescence intensity of Ca2 + in H9c2 cells increased from (16.62 ± 0.89) to (21.48 ± 0.80), (25.68 ± 0.69) and ( 19.84 ± 0.66) (P <0.01). 0.1, 1μmol·L -1 Dio had no significant effect on the mitochondrial membrane potential of H9c2 cells, but the ratio of JC-1 monomer to polymer was increased from (1.14 ± 0.03) to 10μmol·L -1 Dio (1.35 ± 0.06) (P <0.01), which caused the decrease of mitochondrial membrane potential. Conclusions Low and mid-dose Dio can increase LVSP and + dp / dt max, showing positive inotropic effect by increasing intracellular Ca 2+ concentration. Moreover, it does not cause calcium overload while increasing intracellular Ca2 + concentration, but only appears at high concentration.