He C M, Roach M R
Department of Medical Biophysics, University of Western Ontario, London, Canada.
J Vasc Surg. 1994 Jul;20(1):6-13. doi: 10.1016/0741-5214(94)90169-4.
The composition and mechanical properties of abdominal aortic aneurysms (AAAs) were studied.
Stereologic study was used to measure volume fractions of the components of the aortic wall. Histochemical methods with picrosirus red and safranin O were developed to differentiate collagen from ground substance because they are difficult to distinguish from each other on histologic sections. Uniaxial tensile stress tests were carried out on a tensile-testing machine, and a stress-strain curve was plotted for each sample to study the mechanical properties of AAAs. The curves were fitted exponentially so sigma = aeb epsilon, where sigma is stress, epsilon is strain, and a and b are parameters.
In aneurysms (n = 8) the volume fraction of elastin was decreased from 22.7% +/- 5.7% to 2.4% +/- 2.2%, and the volume fraction of smooth muscle cells was decreased from 22.6% +/- 5.5% to 2.2% +/- 2.0%, whereas the volume fraction of collagen and ground substance combined was increased from 54.8% +/- 4.5% to 95.6% +/- 2.5% compared with nonaneurysmal aortas (n = 8). There was no significant difference (p > 0.05) in the ratio of collagen to ground substance (2.1 +/- 0.5 vs 2.0 +/- 0.4) between AAAs and nonaneurysmal aortas. The elastic diagrams showed that AAAs (n = 7) are less distensible and stiffer than nonaneurysmal aortas (n = 5). Parameter a was unchanged (p > 0.5), but parameter b was significantly greater (p < 0.002) for aneurysmal aortas.
Both the composition and mechanical properties of AAAs are different from those of nonaneurysmal aortas. The aneurysms were stiffer, and the volume fractions of collagen and ground substance were increased, whereas the volume fractions of elastin and muscle were decreased in aneurysms.
研究腹主动脉瘤（AAA）的组成和力学性能。
采用体视学研究来测量主动脉壁各成分的体积分数。开发了用苦味酸天狼星红和番红O的组织化学方法来区分胶原蛋白和基质，因为它们在组织切片上难以相互区分。在拉伸试验机上进行单轴拉伸应力试验，并为每个样本绘制应力-应变曲线以研究AAA的力学性能。曲线按指数拟合为σ = ae^bε，其中σ为应力，ε为应变，a和b为参数。
与非动脉瘤性主动脉（n = 8）相比，动脉瘤（n = 8）中弹性蛋白的体积分数从22.7%±5.7%降至2.4%±2.2%，平滑肌细胞的体积分数从22.6%±5.5%降至2.2%±2.0%，而胶原蛋白和基质的总体积分数从54.8%±4.5%增至95.6%±2.5%。AAA与非动脉瘤性主动脉之间胶原蛋白与基质的比例（2.1±0.5对2.0±0.4）无显著差异（p > 0.05）。弹性图显示，AAA（n = 7）比非动脉瘤性主动脉（n = 5）更不易扩张且更硬。参数a无变化（p > 0.5），但动脉瘤性主动脉的参数b显著更大（p < 0.002）。
AAA的组成和力学性能均与非动脉瘤性主动脉不同。动脉瘤更硬，胶原蛋白和基质的体积分数增加，而弹性蛋白和肌肉的体积分数减少。
