同型半胱氨酸通过抑制心肌线粒体自噬诱导线粒体损伤

Homocysteine induces mitochondrial injury via inhibiting myocardial mitophagy

本研究旨在探究同型半胱氨酸(Hcy)与心肌细胞线粒体自噬及线粒体损伤的关系。通过高蛋氨酸饮食法构建高同型半胱氨酸血症(HHcy)大鼠模型,利用免疫荧光共定位染色法和Western blot检测HHcy大鼠心肌的线粒体自噬水平。运用透射电镜观察HHcy大鼠心肌的线粒体形态结构的改变。体外培养H9C2细胞,用Hcy刺激H9C2,利用流式细胞术和JC-1染色法检测线粒体膜电位(MMP)的改变。采用18F-FDG PET/CT在体心肌代谢成像技术检测心肌葡萄糖摄取情况以及直接检测心肌组织的三磷酸腺苷(ATP)含量来评价HHcy大鼠心肌的能量供应情况。结果显示,与正常对照组相比,在HHcy大鼠模型心肌组织中,线粒体自噬水平降低;线粒体排列紊乱,轮廓模糊,膜破损溶解,嵴消失;Hcy刺激的H9C2细胞,线粒体膜电位降低,膜结构完整性受损。HHcy大鼠心肌葡萄糖摄取率增加,ATP含量下降。结果提示,同型半胱氨酸可通过抑制心肌线粒体自噬诱导线粒体损伤。

The purpose of this study is to explore the relationship among homocysteine(Hcy),mitochondrial autophagy and mitochondrial injury in myocardium.The rat model of hyperhomocysteinemia(HHcy)was established by high-Met diet,and the level of mitophagy in myocardium of HHcy rats was detected by immunofluorescence co-localization staining and Western blot.The morphological changes of mitochondria in myocardium of HHcy rats were observed by transmission electron microscope.H9C2 was stimulated by Hcy,and the change of mitochondrial membrane potential(MMP)was detected by flow cytometry and JC-1 staining.18F-FDG PET/CT of myocardial metabolic imaging technology in vivo was used to detect glucose intake and directly detect adenosine triphosphate(ATP)content in myocardial tissue to evaluate the energy supply of HHcy rat myocardium.The results showed that compared with the normal control group,the level of mitophagy in myocardial tissue of HHcy rats model was decreased,mitochondria occurred in disordered arrangement,blurred outline,damaged and dissolved membrane and disappeared cristae.Hcy reduced mitochondrial membrane potential and damaged the overall membrane structure in H9C2.Myocardial glucose uptake rate was increased and ATP content was reduced in HHcy rats.This study suggested that Hcy could induce mitochondrial injury via inhibiting myocardial mitophagy.