Canham P B, Talman E A, Finlay H M, Dixon J G
Department of Medical Biophysics, University of Western Ontario, London, Canada.
Connect Tissue Res. 1991;26(1-2):121-34. doi: 10.3109/03008209109152168.
The mechanical properties of collagen as a biopolymer ensures that collagen has a significant influence on the mechanical behavior of the host tissue. Structural organization is a key to that influence. We have assessed this relationship quantitatively in the tunica media of arteries from the heart and brain, using the polarizing light microscope and Universal stage. Arteries from 22 autopsies were isolated, cannulated and fixed with 10% buffered formalin, at a distending pressure spanning normal values in vivo. We prepared the tissue for light microscopy, with paraffin embedding, sectioning at 7 microns, and staining with picrosirius red to enhance the natural birefringence of medial collagen. Individual measurements, 30 to 50 per arterial section, referenced against the central axis of the vessel segment, revealed a coherent organization, with an average orientation which was within 1 to 2 degrees of being perfectly concentric for all artery segments. Analysis was done with Lambert projections and circular statistics. We calculated the circular standard deviation, which was 5.2 degrees for 27 brain arteries (S.D. 1.9 degrees) and 5.6 degrees (S.D. 2.1 degrees), for 5 coronary arteries sectioned at less than 15 degrees. Our interpretation is that medial collagen can be strained even though highly aligned, revealing a mechanical property which contrasts that of type I collagen.
胶原蛋白作为一种生物聚合物的力学性能确保了它对宿主组织的力学行为有重大影响。结构组织是这种影响的关键。我们使用偏光显微镜和万能载物台，对来自心脏和大脑的动脉中膜的这种关系进行了定量评估。从22例尸检中分离出动脉，插管并用10%缓冲福尔马林固定，在体内正常压力范围内进行扩张。我们对组织进行光镜检查准备，采用石蜡包埋，切成7微米厚的切片，并用苦味酸天狼星红染色以增强中膜胶原蛋白的自然双折射。每个动脉切片进行30到50次单独测量，以血管段的中心轴为参考，结果显示出一种连贯的组织，所有动脉段的平均取向与完全同心的偏差在1到2度以内。使用兰伯特投影和圆形统计进行分析。我们计算了圆形标准差，27条脑动脉的圆形标准差为5.2度（标准差1.9度），5条冠状动脉在小于15度处切片的圆形标准差为5.6度（标准差2.1度）。我们的解释是，即使中膜胶原蛋白高度排列，它仍可被拉伸，这揭示了一种与I型胶原蛋白不同的力学特性。
