Wang Shang, Singh Manmohan, Tran Thuy Tien, Leach John, Aglyamov Salavat R, Larina Irina V, Martin James F, Larin Kirill V
Department of Molecular Physiology and Biophysics, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA.
Equal contribution.
Biomed Opt Express. 2018 Jan 23;9(2):728-742. doi: 10.1364/BOE.9.000728. eCollection 2018 Feb 1.
Myocardial infarction (MI) leads to cardiomyocyte loss, impaired cardiac function, and heart failure. Molecular genetic analyses of myocardium in mouse models of ischemic heart disease have provided great insight into the mechanisms of heart regeneration, which is promising for novel therapies after MI. Although biomechanical factors are considered an important aspect in cardiomyocyte proliferation, there are limited methods for mechanical assessment of the heart in the mouse MI model. This prevents further understanding the role of tissue biomechanics in cardiac regeneration. Here we report optical coherence elastography (OCE) of the mouse heart after MI. Surgical ligation of the left anterior descending coronary artery was performed to induce an infarction in the heart. Two OCE methods with assessment of the direction-dependent elastic wave propagation and the spatially resolved displacement damping provide complementary analyses of the left ventricle. In comparison with sham, the infarcted heart features a fibrotic scar region with reduced elastic wave velocity, decreased natural frequency, and less mechanical anisotropy at the tissue level at the sixth week post-MI, suggesting lower and more isotropic stiffness. Our results indicate that OCE can be utilized for nondestructive biomechanical characterization of MI in the mouse model, which could serve as a useful tool in the study of heart repair.
心肌梗死（MI）会导致心肌细胞丧失、心脏功能受损以及心力衰竭。对缺血性心脏病小鼠模型的心肌进行分子遗传学分析，极大地增进了我们对心脏再生机制的理解，这为MI后的新型治疗带来了希望。尽管生物力学因素被认为是心肌细胞增殖的一个重要方面，但在小鼠MI模型中，对心脏进行力学评估的方法有限。这阻碍了我们进一步了解组织生物力学在心脏再生中的作用。在此，我们报告了MI后小鼠心脏的光学相干弹性成像（OCE）。通过手术结扎左冠状动脉前降支来诱导心脏梗死。两种OCE方法，即评估方向依赖性弹性波传播和空间分辨位移阻尼，可对左心室进行互补分析。与假手术组相比，梗死心脏在MI后第6周在组织水平上表现为纤维化瘢痕区域，弹性波速度降低、固有频率下降且机械各向异性降低，表明刚度更低且各向同性更强。我们的结果表明，OCE可用于对小鼠模型中的MI进行非破坏性生物力学表征，这可作为心脏修复研究中的一种有用工具。
