复律宁颗粒对miR-1介导的缺血性心律失常的保护作用及机制研究

MicroRNA, highly expressed in cells of cardiovascular system, is an important regulator of cardiomyocyte function. MiR-1 is known to play an important role in ischemia-induced arrhythmias. Studies have shown elevated expression of miR-1 in infarct heart tissues both of rats and human. The elevated expression of miR-1 can lead to ischemia-induced arrhythmias in rats, while decreased expression can protect ischemic hearts. Therefore, miR-1 is a therapy target for ischemia-induced arrhythmias. In this research with rats of myocardial infarction as models, we'll study the comprehensive therapeutic effects of Fulvning Granule on arrhythmias, optimal dose and separated complex prescription of Fulvning Granule based on the results of hemodynamics, arrhythmias grades, evaluation of infarct size, qualification of miR-1 and change of major signal molecule on AC-cAMP-PKA signaling pathway. For the separated complex prescription which inhibits miR-1 expression most efficiently, we will qualify miR-1, Cx, Kir2.1 and SRF as well as do patch clamp recording of Ik1. In conclusion, we will study the mechanism of Fulvning Granule on ischemia-induced arrhythmias in a deep way focusing the expression of miR-1.

微小RNA( miRNAs)在心血管系统高度表达，是心肌细胞功能的重要调节因子，其中miR-1主要在缺血性心律失常中起作用。研究证明，在大鼠心肌梗死和临床心肌梗死患者的心室中都发现miR-1表达升高，miR-1表达的升高可诱发大鼠缺血性心律失常的发生，miR-1表达的下调可保护缺血心脏。故将miR-1作为治疗靶点可起到抗缺血性心律失常的作用。本研究以心肌梗死大鼠为模型，从血流动力学、心律失常分级、梗死面积评估、miR-1水平量化测定、β肾上腺受体-cAMP-PKA信号通路上主要信号分子表达的变化的角度，观察复律宁颗粒抗心律失常的整体疗效、筛选最优剂量。围绕miR-1的表达，深入研究复律宁颗粒对缺血性心律失常的作用机制。

目的：本研究以心肌梗死大鼠为模型，从血流动力学、心律失常分级、梗死面积评估、miR-1水平量化测定、β肾上腺受体-cAMP-PKA信号通路上主要信号分子表达变化的角度，观察复律宁颗粒抗心律失常的整体疗效、筛选最优剂量。围绕miR-1的表达，深入研究复律宁颗粒对缺血性心律失常的作用机制。.方法：第一部分实验：50只SD大鼠分为假手术组、MI+生理盐水组、MI+复律宁小剂量组、MI+复律宁中剂量组、MI+复律宁大剂量组。术后复律宁小、中、大剂量组每天分别给予复律宁2.6、5.2、10.4g/kg，假手术组、生理盐水组每天给予盐水灌胃，连续四周。术后四周进行血流动力学测定、心律失常分级、梗死面积评估和miR-1水平量化确定复律宁最优剂量组。第二部分实验：100只SD大鼠分为假手术组、MI+生理盐水组、MI+复律宁中剂量组、MI+普萘洛尔组、MI+复律宁中剂量+普萘洛尔组。术后复律宁中剂量组每天给予5.2g/kg，普萘洛尔组每天给予5mg/kg，复律宁中剂量+普萘洛尔组每天给予复律宁5.2g/kg+普萘洛尔5mg/kg，假手术组、生理盐水组每天给予盐水灌胃，连续四周。术后四周进行血流动力学测定、心律失常分级、梗死面积评估、miR-1水平量化、SRF表达测定以及β肾上腺受体-cAMP-PKA信号通路上主要信号分子表达的变化（PKA表达测定）。.结果：通过冠状动脉左前降支结扎，成功建立了心肌梗死大鼠模型。第一部分实验：复律宁颗粒可不同程度改善血流动力学指标，缩小心肌梗死面积，抑制miR-1的表达，筛选出复律宁最优剂量为中剂量组。第二部分实验：复律宁颗粒与普萘洛尔联合可明显改善血流动力学各项指标，缩小心肌梗死面积，抑制miR-1的表达，抑制了PKA、SRF的蛋白表达。.结论：复律宁颗粒通过β肾上腺素受体-cAMP-PKA信号通路调控miR-1的表达而发挥抗心律失常作用。复律宁颗粒联合普萘洛尔治疗能在多方面更好地改善心梗后心脏功能及形态。