Smith Rebecca M, Matiukas Arvydas, Zemlin Christian W, Pertsov Arkady M
Department of Pharmacology, SUNY Upstate Medical University, Syracuse, New York 13210, USA.
Microsc Res Tech. 2008 Jul;71(7):510-6. doi: 10.1002/jemt.20579.
Mapping the myocardial fiber organization is important for assessing the electrical and mechanical properties of normal and diseased hearts. Current methods to determine the fiber organization have several limitations: histological sectioning mechanically distorts the tissue and is labor-intensive, while diffusion tensor imaging has low spatial resolution and requires expensive MRI scanners. Here, we utilized optical clearing, a fluorescent dye, and confocal microscopy to create three-dimensional reconstructions of the myocardial fiber organization of guinea pig and mouse hearts. We have optimized the staining and clearing procedure to allow for the nondestructive imaging of whole hearts with a thickness up to 3.5 mm. Myocardial fibers could clearly be identified at all depths in all preparations. We determined the change of fiber orientation across strips of guinea pig left ventricular wall. Our study confirms the qualitative result that there is a steady counterclockwise fiber rotation across the ventricular wall. Quantitatively, we found a total fiber rotation of 105.7+/-14.9 degrees (mean+/-standard error of the mean); this value lies within the range reported by previous studies. These results show that optical clearing, in combination with a fluorescent dye and confocal microscopy, is a practical and accurate method for determining myocardial fiber organization.
绘制心肌纤维结构对于评估正常和患病心脏的电学和力学特性至关重要。目前确定纤维结构的方法存在若干局限性：组织学切片会使组织发生机械变形且劳动强度大，而扩散张量成像空间分辨率低且需要昂贵的磁共振成像扫描仪。在此，我们利用光学透明化、一种荧光染料和共聚焦显微镜对豚鼠和小鼠心脏的心肌纤维结构进行三维重建。我们优化了染色和透明化程序，以便对厚度达3.5毫米的完整心脏进行无损成像。在所有标本的各个深度都能清晰识别心肌纤维。我们测定了豚鼠左心室壁条带上纤维方向的变化。我们的研究证实了定性结果，即整个心室壁存在稳定的逆时针纤维旋转。定量分析发现，纤维总旋转角度为105.7±14.9度（平均值±平均标准误差）；该值在先前研究报告的范围内。这些结果表明，光学透明化结合荧光染料和共聚焦显微镜是一种确定心肌纤维结构的实用且准确的方法。
