Certain morphological parameters of the skeletal muscle tissue can be better understood via 3D considerations. Fluorescent confocal microscopy of thick tissue sections is a well-established method for visualising and measuring skeletal muscle fibres and surrounding capillaries in 3D. However, thick tissue sections are prone to deformations which may significantly influence some stereological and morphometric results like muscle fibre diameter and capillary length, but not dimensionless parameters like object number and Euler-Poincaré characteristics. To better understand this phenomenon, we studied the horizontal deformation of thick (100 μm) transverse skeletal muscle sections, by comparing the muscle fibre diameters measured on thick sections to muscle fibre diameters measured on thin (10 μm) sections of the same sample. Diameter changes were further correlated with shrinkage in the Z direction (axial shrinkage) and deviation of the muscle fibre preferential axis from the Z-axis. We showed that the thick sections dilated in horizontal and shrunk in Z direction, and that the magnitude of horizontal dilation was associated with the magnitude of shrinkage in the Z direction. The latter was more pronounced in transversely than obliquely cut tissue sections. The results emphasize that even when shrinkage in the Z direction can be corrected using calibration, it is important to optimise histological protocols to minimize the Z-axis collapse that could cause horizontal dilation. This article is protected by copyright. All rights reserved.

中文翻译：

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共聚焦显微镜观察骨骼肌厚切片的水平变形

通过 3D 考虑可以更好地理解骨骼肌组织的某些形态参数。厚组织切片的荧光共聚焦显微镜是一种行之有效的方法，用于在 3D 中可视化和测量骨骼肌纤维和周围毛细血管。然而，厚组织切片容易发生变形，这可能会显着影响一些体视学和形态测量结果，如肌纤维直径和毛细血管长度，但不会影响无量纲参数，如对象数和欧拉-庞加莱特性。为了更好地理解这一现象，我们研究了厚（100 μm）横向骨骼肌切片的水平变形，通过比较在厚切片上测量的肌纤维直径与在同一样品的薄（10 μm）切片上测量的肌纤维直径。直径变化进一步与 Z 方向的收缩（轴向收缩）和肌肉纤维优先轴与 Z 轴的偏差相关。我们发现厚截面在水平方向上膨胀并在 Z 方向上收缩，并且水平膨胀的大小与 Z 方向上的收缩大小相关。后者在横向比斜切组织切片中更明显。结果强调，即使 Z 方向的收缩可以使用校准进行校正，重要的是优化组织学协议以最小化可能导致水平扩张的 Z 轴塌陷。本文受版权保护。版权所有。