Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, 15213, USA.
Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, 15213, USA.
Sci Rep. 2017 Sep 21;7(1):12065. doi: 10.1038/s41598-017-12006-1.
Advances in imaging have made it increasingly common to study soft tissues without first embedding them in plastic or paraffin and without using labels or stains. The process, however, usually still involves fixation and cryosectioning, which could deform the tissues. Our goal was to quantify the morphological changes of ocular tissues caused by formalin fixation and cryosectioning. From each of 6 porcine eyes, 4 regions were obtained: cornea, equatorial and posterior sclera, and posterior pole containing the optic nerve head. Samples were imaged using visible light microscopy fresh, 1-minute and 24-hours post-fixation, and post-cryosectioning. Effects were assessed by 14 parameters representing sample size and shape. Overall, formalin fixation and sectioning caused only minimal changes to the ocular tissues, with average percentage parameter differences of 0.1%, 1%, and 1.2% between fresh and post-fixing by 1 minute, 24 hours, and post-cryosectioning, respectively. Parameter changes were not directional, and were only weakly dependent on the duration of fixation and the region of the eye. These results demonstrate that formalin fixation and cryosectioning are good choices for studying ocular tissue morphology and structure, as they do not cause the large tissue shrinkage or distortions typically associated with other, more complicated, techniques.
成像技术的进步使得人们越来越倾向于在不首先将软组织嵌入塑料或石蜡中、不使用标记物或染色剂的情况下对其进行研究。然而，该过程通常仍然涉及固定和冷冻切片，这可能会导致组织变形。我们的目标是量化甲醛固定和冷冻切片对眼部组织形态的变化。从 6 只猪眼的每只眼中获得 4 个区域：角膜、赤道和后巩膜以及包含视神经头的后极。新鲜、固定后 1 分钟和 24 小时以及冷冻切片后，使用可见光显微镜对样本进行成像。通过代表样本大小和形状的 14 个参数评估效果。总体而言，甲醛固定和切片仅对眼部组织造成最小的变化，新鲜和固定后 1 分钟、24 小时以及冷冻切片后分别有 0.1%、1%和 1.2%的平均百分比参数差异。参数变化没有方向性，仅与固定时间和眼部区域的持续时间有弱相关性。这些结果表明，甲醛固定和冷冻切片是研究眼部组织形态和结构的良好选择，因为它们不会导致与其他更复杂技术相关的大组织收缩或变形。
