Comparative assessment of liver tissue:from microstructural and mesoscale vascular architecture to macroscopic mechanics  

肝脏中心和边缘区域的异同:从微观和介观结构到宏观力学性能

作　　者：Wei Kang Kaixin Sun Lizhen Wang Yubo Fan 康巍;孙开新;王丽珍;樊瑜波(Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education,Beijing Advanced Innovation Center for Biomedical Engineering,School of Biological Science and Medical Engineering,Beihang University,Beijing 100083,China;School of Engineering Medicine,Beihang University,Beijing 100083,China)

机构地区：[1]Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education,Beijing Advanced Innovation Center for Biomedical Engineering,School of Biological Science and Medical Engineering,Beihang University,Beijing 100083,China [2]School of Engineering Medicine,Beihang University,Beijing 100083,China

出　　处：《Acta Mechanica Sinica》2024年第7期195-205,共11页力学学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.U2241273,12172034,U20A20390,and 11827803);the Beijing Municipal Natural Science Foundation(Grant No.7212205);the 111 project(Grant No.B13003);the Fundamental Research Funds for the Central Universities.

摘　　要：Accurately characterizing the liver's mechanical properties is of paramount importance for disease diagnosis,treatment,surgical prosthetic modeling,and impact injury dummies.However,due to its inherent biological soft tissue nature,the characterization of mechanical behavior varies across testing methods and sample types.In this study,we employed transmission electron microscope and Micro CT to observe the morphology of the marginal and center of rat livers and conducted macroscopic mechanical tests to characterize their elasticity and viscoelasticity.The results revealed that the central region displayed higher metabolic levels,elongated mitochondria,and an abundance of rough endoplasmic reticulum at the microscale.At the mesoscale,larger diameter portal veins were mainly distributed in the central region,while smaller diameter arteries were predominantly located at the periphery.At the macroscale,under a strain rate of 0.0167 s^(-1),no significant differences were observed in the elastic properties between the two regions.However,as the strain rate increased up to 0.167 s^(-1),the central region displayed higher porosity,resulting in reduced liquid loss,increased hardness,and higher viscosity compared to the periphery.Consequently,the liver demonstrated overall heterogeneity,with isotropic models suitable for the peripheral region,while more intricate models may be required to capture the complexity of the central region with its intricate vasculature.精准描述肝脏的力学性能对于疾病诊断和治疗,外科假体建模和冲击损伤模型具有重要意义.然而,由于其固有的生物软组织特性,测试方法和样本类型等对于其力学行为的表征结果总是不尽相同.在本研究中,我们采用了透射电镜(TEM)和Micro CT观察大鼠肝脏内外缘的形貌并进行宏观力学试验表征弹性和黏弹性.结果显示,在微观尺度上,中心区域表现出较高的新陈代谢水平,线粒体细长且更丰富的内质网,在介观尺度上,较大直径的门静脉主要分布在中心区域,而较小直径的动脉主要位于边缘.在宏观尺度上,两区域在应变率为0.0167 s^(-1)时弹性性能无明显差异,中心区域相对于边缘孔隙率更高且随着应变率上升到0.167 s^(-1),减少了水分的流失变得更硬且显示更高的黏性.因此肝脏整体表现出了异质性,各向同性模型适用于肝脏边缘区域,对于血管复杂的中心区域可能需要更复杂的模型.

关 键 词：LIVER Mechanical properties Micro and macro tests 

分 类 号：O3[理学—力学]