Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, AUVA Research Center, Vienna, Austria.
Karl Donath Laboratory for Hard Tissue and Biomaterial Research, University Clinic of Dentistry, Medical University Vienna, Vienna, Austria.
Contrast Media Mol Imaging. 2019 Mar 27;2019:7483745. doi: 10.1155/2019/7483745. eCollection 2019.
Microcomputed tomography (CT) is widely used for the study of mineralized tissues, but a similar use for soft tissues is hindered by their low X-ray attenuation. This limitation can be overcome by the recent development of different staining techniques. Staining with Lugol's solution, a mixture of one part iodine and two parts potassium iodide in water, stands out among these techniques for its low complexity and cost. Currently, Lugol staining is mostly used for anatomical examination of tissues. In the present study, we seek to optimize the quality and reproducibility of the staining for visualization of soft tissues in the context of a peripheral nerve regeneration model in the rat. We show that the staining result not only depends on the concentration of the staining solution but also on the amount of stain in relation to the tissue volume and composition, necessitating careful adaptation of the staining protocol to the respective specimen tissue. This optimization can be simplified by a stepwise staining which we show to yield a similar result compared to staining in a single step. Lugol staining solution results in concentration-dependent tissue shrinkage which can be minimized but not eliminated. We compared the shrinkage of tendon, nerve, skeletal muscle, heart, brain, and kidney with six iterations of Lugol staining. 60 ml of 0.3% Lugol's solution per cm of tissue for 24 h yielded good results on the example of a peripheral nerve regeneration model, and we were able to show that the regenerating nerve inside a silk fibroin tube can be visualized in 3D using this staining technique. This information helps in deciding the region of interest for histological imaging and provides a 3D context to histological findings. Correlating both imaging modalities has the potential to improve the understanding of the regenerative process.
微计算机断层扫描（CT）广泛应用于研究矿化组织，但软组织的类似应用受到其低 X 射线衰减的阻碍。通过最近开发的不同染色技术可以克服这一限制。在这些技术中，碘和碘化钾以 1:2 混合在水中的卢戈氏溶液染色因其低复杂性和低成本而脱颖而出。目前，卢戈氏染色主要用于组织的解剖检查。在本研究中，我们旨在优化染色的质量和重现性，以便在大鼠周围神经再生模型中可视化软组织。我们表明，染色结果不仅取决于染色溶液的浓度，还取决于与组织体积和组成相关的染色量，因此需要仔细调整染色方案以适应各自的标本组织。通过逐步染色可以简化这种优化，我们证明与一步染色相比，它可以产生相似的结果。卢戈氏染色溶液会导致与浓度相关的组织收缩，这种收缩虽然可以最小化但无法完全消除。我们比较了肌腱、神经、骨骼肌、心脏、大脑和肾脏在六次卢戈氏染色中的收缩情况。对于周围神经再生模型，每厘米组织使用 60ml 0.3%的卢戈氏溶液染色 24 小时可以得到良好的结果，我们能够表明，使用这种染色技术可以在 3D 中可视化丝素纤维管内的再生神经。这些信息有助于确定组织学成像的感兴趣区域，并为组织学发现提供 3D 背景。将两种成像方式相关联有可能提高对再生过程的理解。
