心肌纤维化是心肌梗死、糖尿病心肌病等多种心血管疾病的共同病理生理过程。研究表明,心肌纤维化与线粒体功能障碍密切相关,近期研究证实线粒体Na+/Ca2+交换体(NCLX)介导的Ca2+稳态对维持线粒体功能至关重要。本课题前期研究发现,苓桂术甘汤能够抑制模型动物心肌纤维化、改善心功能,并能降低心肌细胞线粒体膜电位,提高ROS清除率,改善氧化应激损伤。据此我们推测苓桂术甘汤可能通过上调NCLX表达,促进Ca2+外流,抑制线粒体损伤,限制心肌纤维化。故本项目拟分别构建NCLX敲除和过表达模型,运用透射电镜、海马细胞能量检测仪、流式细胞仪等技术,评估苓桂术甘汤对心肌细胞纤维化、线粒体功能线粒体NCLX和Ca2+ 浓度的影响,以及该方抑制线粒体损伤和心肌纤维化作用与NCLX调控的Ca2+浓度的相关性,初步阐明其维护线粒体功能、抑制心肌纤维化作用机制,为该方治疗心血管疾病提供理论和实验依据。

Myocardial fibrosis (MF) is a common pathophysiological process involving in many cardiovascular diseases such as myocardial infarction and diabetic cardiomyopathy. Some studies showed that mitochondrial dysfunctions played a key role in the process of myocardial fibrosis. And a recent study demonstrated that Ca2+ homeostasis mediated by the mitochondrial Na+/Ca2+ exchanger（NCLX） is essential for the mitochondrial function. Our previous studies found that Lingguizhugan decoction could inhibit the myocardial fibroblasts and improve heart function in model animals. In addition, it could reduce mitochondrial membrane potential and clear ROS in myocardial cells. Therefore, we proposed the hypothesis that Lingguizhugan decoction could promote the extrusion of Ca2+ by the up-regulating expression of NCLX, which would help to inhibit mitochondrial damage and limit myocardial fibrosis. In this project, we will delete or overexpress NCLX in cells respectively. By using all kinds of techniques such as transmission electron microscopy, hippocampal cell energy detector and flow cytometry, we will evaluate the effects of Lingguizhugan decoction on mitochondrial function and fibrosis in myocardial cells, as well as mitochondrial NCLX and Ca2+ concentration. We will further explore the correlation of mitochondrial injury, myocardial fibrosis and the concentration of Ca2+ regulated by NCLX in cells or animals treated by Lingguizhugan decoction. Our study will elucidate the mechanism of Lingguizhugan decoction in inhibiting myocardial fibrosis, which may provide theoretical basis and experimental supports for Lingguizhugan decoction in treating cardiovascular diseases.