隐丹参酮对氯化钙-乙酰胆碱诱导的大鼠心房颤动的影响

Effect of cryptotanshinone on calcium chloride-acetylcholine-inducedatrial fibrillation in rats

关键词:  隐丹参酮  瞬时外向钾通道  心房颤动  全细胞膜片钳  心房肌细胞  离子通道。

Key words:  Cryptotanshione  Transient outward potassium channel  Atrial fibrillation  Atrial myocytes  Whole cell patch clamp

摘要:

目的研究隐丹参酮(Cryptotanshinone,CTS)对SD大鼠实验性房颤(atrial fibrillation,AF)的影响,并探究其离子通道层面可能的作用机制。方法采用尾静脉注射氯化钙-乙酰胆碱的方法制备大鼠体内阵发性AF模型；使用Langendorff逆行灌流、三步梯度复钙法分离满足实验要求的单个大鼠心房肌细胞；应用全细胞膜片钳技术观察、记录和分析15、30、60 μmol/LCTS对大鼠心房肌细胞瞬时外向钾通道电流(I_to)的影响。结果体内实验结果表明,与对照组相比,5、10、20 mg/kg的CTS预防给药逐渐延长了模型动物AF诱导时间, 而AF持续时间逐渐降低(n=8,P<0.01),AF发生率则无明显影响。膜片钳实验结果表明,15、30、60μmol/L的CTS可使I_to峰值逐渐降低,表现出明显的浓度依赖性抑制(n=10,P<0.01)。通道动力学研究方面,15、30、60 μmol/LCTS可使I_to的电流-电压关系曲线明显下移；稳态激活曲线无明显变化；各浓度下的稳态失活曲线依次左移,半数失活电压(V_1/2-inactive)渐次降低(n=10,P<0.01)；失活后恢复曲线右移,恢复时间常数(τ)逐渐延长(n=9,P<0.01)。以上结果表明,CTS能够拮抗模型动物AF的发生,抑制I_to以及I_to的失活和失活后恢复的动力学过程。结论CTS具有抗氯化钙-乙酰胆碱诱导的大鼠AF作用,此效应的产生可能与药物抑制I_to并改变其动力学过程有关。

Abstract:

ABSTRACT: OBJECTIVE To investigate the effects of Cryptotanshinone (CTS) on experimental atrial fibrillation (AF) in SD rats and explore its possible ion channel mechanisms. we used intravenous injection of calcium chloride-acetylcholine to induce AF in SD rats in vivo. METHODS Single rat atrial myocytes were isolated by Langendorff retrograde perfusion and three-step gradient calcium extraction method that met the experimental requirements. Whole-cell patch-clamp technique was used to observe, record, and analyze the effects of 15, 30, and 60 μmol/LCTS on the transient outward potassium current (Ito) of rat atrial myocytes. RESULTS The results showed that in vivo experiments indicated that compared with the control group, the CTS preventive administration at doses of 5, 10, and 20 mg/kggradually prolonged the time of AF induction in the experimental animals, while the duration of AF decreased gradually (n=8, P<0.01), and the incidence of AF had no significant influence. The results of the patch-clamp experiments showed that 15, 30, and 60 μmol/LCTS gradually reduced the peak value of Ito, showing a concentration-dependent inhibition (n=10, P<0.01). In terms of channel kinetics, 15, 30, and 60 μmo/LCTS significantly shifted the Ito current-voltage relationship curve downward; the steady-state activation curve showed no significant change; the steady-state inactivation curves were sequentially shifted to the left in each concentration, with the half-inactivation voltage (V1/2-inactive) gradually decreasing (n=10, P<0.01); the inactivation recovery curve was shifted to the right, with the recovery time constant (τ) gradually increasing (n=9, P<0.01). These results indicated that CTS could inhibit the occurrence of AF in the model animals, suppress Ito, and regulate the dynamic processes of Ito inactivation and recovery. CONCLUSION CTS has an anti-calcium-acetylcholine induced AF effect in rats, and the occurrence of this effect may be related to the inhibition of Ito and alteration of its kinetic course by the drug.