Mechanical Characterization and Constitutive Modeling of Rabbit Aortas in Health and Diabetes

Q4 Biochemistry, Genetics and Molecular Biology

Molecular & Cellular Biomechanics Pub Date : 2019-02-21 DOI:10.32604/MCB.2019.05721

Zhi Zhang, J. Tong

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引用次数: 1

Abstract

Diabetes is a major risk factor to cause macrovascular diseases and plays a pivotal role in aortic wall remodeling. However, the effects of diabetes on elastic properties of aortas remain largely unknown. Thirty adult rabbits (1.6-2.2 kg) were collected and the type I diabetic rabbit model was induced by injection of alloxan. A total of 15 control and 15 diabetic rabbit (abdominal) aortas were harvested. Uniaxial and biaxial tensile tests were performed to measure ultimate tensile strength and to characterize biaxial mechanical behaviors of the aortas. A material model was fitted to the biaxial experimental data to obtain constitutive parameters. Histological and mass fraction analyses were performed to investigate the underlying microstructure and dry weight percentages of elastin and collagen in the control and the diabetic aortas. No statistically significant difference was found in ultimate tensile strength between the control and the diabetic aortas. Regarding biaxial mechanical responses, the diabetic aortas exhibited significantly lower extensibility and significantly higher tissue stiffness than the control aortas. Notably, tissue stiffening occurred in both circumferential and axial directions for the diabetic aortas; however, mechanical anisotropy does not change significantly. The material model was able to fit biaxial experimental data very well. Histology showed that a number of isolated foam cells were embedded in the diabetic aortas and hyperplasia of collagen was identified. The dry weight percentages of collagen within the diabetic aortas increased significantly as compared to the control aortas, whereas no significant change was found for that of elastin. The results suggest that the diabetes impairs elastic properties and alters microstructure of the aortas and consequently, these changes may further contribute to complex aortic wall remodeling.

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健康和糖尿病兔主动脉的力学特性和本构模型

糖尿病是引起大血管疾病的主要危险因素，在主动脉壁重构中起着关键作用。然而，糖尿病对主动脉弹性特性的影响在很大程度上仍然未知。取成年家兔30只(1.6 ~ 2.2 kg)，注射四氧嘧啶诱导1型糖尿病家兔模型。取糖尿病兔(腹)主动脉15条，对照组15条。进行了单轴和双轴拉伸试验，以测量极限拉伸强度并表征主动脉的双轴力学行为。将材料模型拟合到双轴实验数据中，得到本构参数。通过组织学和质量分数分析，研究了对照组和糖尿病主动脉中弹性蛋白和胶原蛋白的微观结构和干重百分比。对照组与糖尿病主动脉的极限抗拉强度无统计学差异。在双轴力学反应方面，糖尿病主动脉的延伸性明显低于对照主动脉，而组织刚度明显高于对照主动脉。值得注意的是，糖尿病主动脉在周向和轴向都发生了组织硬化;但力学各向异性变化不明显。材料模型能很好地拟合双轴实验数据。组织学显示，糖尿病主动脉内包埋有大量分离的泡沫细胞，胶原增生。与对照主动脉相比，糖尿病主动脉内胶原蛋白的干重百分比显著增加，而弹性蛋白的干重百分比无显著变化。结果表明，糖尿病损害了主动脉的弹性特性，改变了主动脉的微观结构，这些变化可能进一步导致复杂的主动脉壁重塑。

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来源期刊

Molecular & Cellular Biomechanics CELL BIOLOGYENGINEERING, BIOMEDICAL&-ENGINEERING, BIOMEDICAL

CiteScore

1.70

自引率

0.00%

发文量

期刊介绍： The field of biomechanics concerns with motion, deformation, and forces in biological systems. With the explosive progress in molecular biology, genomic engineering, bioimaging, and nanotechnology, there will be an ever-increasing generation of knowledge and information concerning the mechanobiology of genes, proteins, cells, tissues, and organs. Such information will bring new diagnostic tools, new therapeutic approaches, and new knowledge on ourselves and our interactions with our environment. It becomes apparent that biomechanics focusing on molecules, cells as well as tissues and organs is an important aspect of modern biomedical sciences. The aims of this journal are to facilitate the studies of the mechanics of biomolecules (including proteins, genes, cytoskeletons, etc.), cells (and their interactions with extracellular matrix), tissues and organs, the development of relevant advanced mathematical methods, and the discovery of biological secrets. As science concerns only with relative truth, we seek ideas that are state-of-the-art, which may be controversial, but stimulate and promote new ideas, new techniques, and new applications.