Rheological properties of the common carotid artery in young versus aged cadavers

doi:10.3969/j.issn.2095-4344.2017.16.012

Abstract

Abstract:

BACKGROUND: With age and blood pressure increasing, the damaged elastic membrane induced by degenerative vascular matrix results in calcium and collagen deposition, and finally expanded large arteries and aortas are easy to cause arteriosclerosis.
OBJECTIVE: To compare the rheological properties of the common carotid artery in the youth and elderly, thus providing a basis for the study on the pathogenesis of atherosclerosis of the common carotid artery.
METHODS: Common carotid arteries were respectively removed from the young and elderly cadavers. Ten samples from each group were randomly selected, and subjected to stress relaxation and creep tests. Meanwhile, one sample from each group was selected for histological observation.
RESULTS AND CONCLUSION: The stress at 7 200 s in the young group was significantly decreased compared with the elderly group (P < 0.05). The strain at 7 200 s in the young group was significantly increased compared with the elderly group (P < 0.05). Scanning electron microscope observed that in the elderly group, there were lipid plaques and foam cell accumulation; the internal elastic lamina and middle elastic plate presented with degeneration, rupture and disintegration; and there were abundant plaques and inflammatory cells in the intimal and media, which characterized as atherosclerosis. While no lipid plaques were found in the young group. These results indicate that the elastic fibers and collagen fibers in the common carotid artery arrange in disorder as age increases, and the rheological properties are also changed.

中国组织工程研究杂志出版内容重点：组织构建；骨细胞；软骨细胞；细胞培养；成纤维细胞；血管内皮细胞；骨质疏松；组织工程

Key words: Carotid Artery, Common, Stress, Mechanical, Rheology, Tissue Engineering

CLC Number:

R318

Xu Dong-hui, Huang Shu-hua, Li Xin-ying, Li Dong-yuan. Rheological properties of the common carotid artery in young versus aged cadavers[J]. Chinese Journal of Tissue Engineering Research, 2017, 21(16): 2527-2533.

Figures/Tables 7

2.1 青年颈总动脉组和老年颈总动脉组试样的应力松弛曲线对施加初始应力16.0 kPa的2组试样的主要时间点数据进行曲线拟合，应力松弛曲线见图1。对施加初始应力22.5 kPa的2组试样的主要时间点的数据进行曲线拟合，应力松弛曲线见图2。由图1可知，青年颈总动脉组和老年颈总动脉组试样施加初始应力16.0 kPa应力松弛实验最初600 s应力下降较快，之后应力缓慢下降，7 200 s时2组试样应力松弛曲线基本趋于水平，2组试样应力松弛曲线基本呈对数关系变化。图1A中青年颈总动脉组0 s时应力为 16.0 kPa，7 200 s时应力为11.4 kPa，应力下降了4.6 kPa。老年颈总动脉组试样0 s时应力为16.0 kPa，7 200 s时应力为12.8 kPa，下降了3.2 kPa，2组试样7 200 s应力下降量差异有显著性意义(P < 0.05)。当初始应力为22.5 kPa时，2组试样应力松弛实验最初600 s应力下降较快，之后应力缓慢下降，7 200 s时应力松弛曲线基本水平，2组试样应力松弛曲线基本呈对数关系变化。图1B中青年颈总动脉组试样0s时应力为22.5 kPa，7 200 s时应力为18.3 kPa，应力下降了4.2 kPa。老年颈总动脉组试样0 s时应力为22.5 kPa，7 200 s时应力为 19.6 kPa，7 200 s应力下降了2.9 kPa，2组试样7 200 s应力下降量差异有显著性意义(P < 0.05)。2组试样施加初始应力为22.5 kPa时的7 200 s应力下降量小于施加初始应力为16.0 kPa时的7 200 s应力下降量，随着恒应变的增加，初始应力增加了，但7 200 s应力下降量不成线性下降，而是呈对数关系变化的。 2.2 青年颈总动脉组和老年颈总动脉组试样的应力松弛函数曲线对施加初始应力16.0 kPa的2组试样的的应力松弛函数数据进行曲线拟合，应力松弛函数曲线见图2A，对施加初始应力22.5 kPa 2组试样的应力松弛函数数据进行曲线拟合，应力松弛函数曲线见图2B。由图2A可知，施加初始应力16.0 kPa时，2组试样0 s时的归一化应力松弛函数值为1，7 200 s应力松弛函数值分别为0.71和0.80，2组式样7 200 s应力松弛函数的下降值差异有显著性意义(P < 0.05)。由图2B可知，施加初始应力22.5 kPa时，2组试样0 s时的归一化应力松弛函数值为1，7 200 s应力松弛函数值分别为0.81和0.87，2组式样7 200 s应力松弛函数下降值差异有显著性意义(P < 0.05)。 2.3 青年颈总动脉组和老年颈总动脉组试样的归一化应力松弛函数方程建立结果由图1可知，应力松弛曲线是以对数关系变化的，因此设[16 ]："

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