Kobielarz Magdalena, Chwiłkowska Agnieszka, Turek Artur, Maksymowicz Krzysztof, Marciniak Monika
Department of Biomedical Engineering, Mechatronics and Theory of Mechanisms, Wroclaw University of Technology, Wrocław, Poland.
Regional Specialist Hospital in Wrocław, Research and Development Centre, Wrocław, Poland.
Acta Bioeng Biomech. 2015;17(2):55-62.
There are two families of fibres taking part in the process of mechanical loads transfer, i.e. elastin and collagen fibres. Their number, spatial arrangement and specific properties determine the capacity of a blood vessels to resist mechanical loads resulting from the impact of blood on vessel walls. The purpose of the present paper is to define the load-bearing capacities of elastin and collagen scaffolds equivalent to natural fibre arrangements of human aorta and produced by selective digestion.
Samples of thoracic human aortas were digested by using phosphate buffer of trypsin at pH 8.0 for 22 hours in order to degrade elastin and by autoclaving followed by incubation in 90% formic acid for 22 hours. The efficacy of digestion was assessed immunohistochemically. Mechanical properties of pre-stretched native and digested samples were determined by uniaxial tensile test.
Samples subjected to autoclaving have been successfully deprived of both types of collagen and elastin has been intact. Treatment with trypsin caused a removal of elastin and the presence of type I and IV collagen was demonstrated. Digestion of aortic samples either by formic acid or trypsin has resulted significantly decreasing mechanical properties in comparison with native samples.
Collagen and elastin scaffold-like stuctures have been effectively produced by selective digestion of thoracic human aorta and their contribution to the load-bearing process was evaluated. Isolated collagen network are more durable and stiffer and less deformable than elastin network, hence are responsible for load-bearing process at higher strain since the range of working of elastin is at lower strain values.
有两类纤维参与机械负荷传递过程，即弹性蛋白纤维和胶原纤维。它们的数量、空间排列及特定属性决定了血管抵抗因血液冲击血管壁而产生的机械负荷的能力。本文的目的是确定通过选择性消化产生的、与人主动脉天然纤维排列等效的弹性蛋白和胶原支架的承载能力。
用人胸主动脉样本，在pH 8.0的胰蛋白酶磷酸盐缓冲液中消化22小时以降解弹性蛋白，然后进行高压灭菌，接着在90%甲酸中孵育22小时。通过免疫组织化学评估消化效果。通过单轴拉伸试验测定预拉伸的天然样本和消化后样本的力学性能。
经过高压灭菌的样本成功去除了两类胶原蛋白，弹性蛋白保持完整。用胰蛋白酶处理导致弹性蛋白被去除，同时证明了I型和IV型胶原的存在。与天然样本相比，用甲酸或胰蛋白酶消化主动脉样本均导致力学性能显著下降。
通过对人胸主动脉进行选择性消化，有效制备了胶原和弹性蛋白支架样结构，并评估了它们在承载过程中的作用。分离出的胶原网络比弹性蛋白网络更耐用、更硬且更不易变形，因此在较高应变下负责承载过程，因为弹性蛋白的工作范围是在较低应变值。
