滚动载荷条件下软骨传质过程的研究

发布时间：2018-05-25 03:38

本文选题：软骨 + 传质　；参考：《天津理工大学》2012年硕士论文

【摘要】：膝关节软骨有承受载荷、缓冲震荡和润滑关节等重要作用，是慢性疾病的多发部位之一。大多数早期软骨组织的病变和重建失败都是因为传质过程无法正常进行的结果。软骨中没有血管、神经，传质过程不仅能维持营养物质、供给废物的代谢，而且提供其对新陈代谢有调节作用的酶类、抑制因子、细胞活性素和生长因子等具有生物活性的大小分子，正常软骨的传质过程的顺利进行需要在一定的外界载荷的。此方面研究不仅利于揭示软骨组织新陈代谢进行的机制，对于临床病变治疗、修复有重大的意义，而且也是软骨组织工程的基础研究内容之一。先前研究表明对于离体软骨样本施加单向压力能够调节软骨的新陈代谢，本课题中根据人体膝关节软骨的受力环境，摒弃对单一方向压缩载荷的模拟，首先使用多角度的宏观的力学环境来研究滚动加载的方式对于软骨传质过程的影响。该方法，以一个新的角度阐述了这种力学环境下基质、流体流动、电势电流以及软骨成分的变化。借鉴于其他生命组织的传质机制和科研方法，本文通过软骨的生理结构、受力环境，实验模拟软骨传质生理过程，，理论上研究生物以及软骨的传质过程的各控制方程，借助现有的商业有限元软件完成滚动条件下软骨传质的浓度场的计算，下面介绍主要研究工作以及成果： 1、实验部分。实验分别选用了罗丹明B和标记硫氰酸罗丹明、四甲基罗丹明标记软骨必需蛋白质葡聚糖，实验组分别在我们自行研制的滚动装置下加载，压缩量为20%，滚速为10cm/s,对照组静态培养。取一定的时间点，把软骨冰冻切片，荧光显微镜下观测实验组、对照组软骨中示踪剂荧光强度来比较各组传质的程度。实验表明，滚动加载力学环境能够促进大分子、小分子在软骨组织中的传质过程。 2、传质数学模型。基于多孔介质三相理论的力学模型，结合热和质量扩散间的数学特性，建立三相的扩散系数和热传导系数之间的等效数值算法，应用应变是热传导系数（即等效后的扩散系数）变化的激励，把三相理论应用于商业有限元软件来解决软骨中的一些问题。 3、计算机仿真。膝关节软骨结构采用多层建模，从受力的最小单元出发，建立软骨传质的滚压加载有限元模型，利用有限元软件ANSYS对软骨的应变激励等效扩散系数变化进行仿真，探索软骨在不同的压缩量、载荷速度因素下，传质过程的影响规律。结果表明，在各种滚动条件下各层软骨中的等效浓度场相对于稳态浓度场都有不同程度的提高。在控制其他变量时，随着压缩量增加，软骨组织各个单元的等效浓度场相对于稳态浓度都有增加，且最大增幅发生在当辊子滚动到大约中间位置处；随着滚速的增加，软骨组织各个单元的温度相对于稳态温度都有增加；对于每一层软骨而言，应力、应变较大部位发生在第二层附近。
[Abstract]:Knee articular cartilage is one of the most common sites of chronic diseases because of its important functions such as bearing load, cushioning concussion and lubricating joint. Most early cartilage lesions and reconstruction failures are due to the failure of mass transfer. There are no blood vessels, nerves, and mass transfer processes in the cartilage that not only maintain the metabolism of nutrients and wastes, but also provide enzymes and inhibitors that regulate metabolism. For bioactive molecules such as cytokines and growth factors, the smooth mass transfer of normal cartilage requires a certain amount of external loading. This study is not only helpful to reveal the mechanism of cartilage metabolism, but also has great significance for the treatment and repair of clinical lesions. It is also one of the basic research contents of cartilage tissue engineering. Previous studies have shown that unidirectional pressure on isolated cartilage samples can regulate the metabolism of cartilage. In this study, according to the stress environment of human knee cartilage, the simulation of compression load in a single direction is abandoned. The effect of rolling loading on mass transfer of cartilage was studied by using multi-angle macro-mechanical environment. In this method, the changes of matrix, fluid flow, potential current and cartilage composition in this kind of mechanical environment are described in a new angle. Based on the mass transfer mechanism and scientific research methods of other living tissues, this paper studies the control equations of the mass transfer process of organism and cartilage theoretically through the physiological structure of cartilage, the stress environment, the experimental simulation of the physiological process of mass transfer of cartilage, and the theoretical study on the control equations of the mass transfer process of organism and cartilage. The current commercial finite element software is used to calculate the concentration field of cartilage mass transfer under rolling condition. 1. Experimental part. Rhodamine B, rhodamine thiocyanate and tetramethyl rhodamine were used to label essential protein glucan in cartilage. The compression was 20 and the rolling speed was 10 cm / s, while the control group was cultured statically. At a certain time point, the chondrocytes were cut into frozen sections, and the fluorescence intensity of tracer in cartilage of experimental group and control group were observed under fluorescence microscope to compare the degree of mass transfer in each group. The experimental results show that the rolling loading environment can promote the mass transfer of macromolecules and small molecules in cartilage tissue. 2. Mathematical model of mass transfer. Based on the mechanical model of the three-phase theory of porous media and the mathematical characteristics between heat and mass diffusion, the equivalent numerical algorithm between the diffusion coefficient and the heat conduction coefficient of the three phase is established. The application of strain is the excitation of the change of heat conduction coefficient (i.e. diffusion coefficient after equivalent). The three-phase theory is applied to the commercial finite element software to solve some problems in cartilage. 3. Computer simulation. To explore the influence law of mass transfer process of cartilage under different compression amount and loading speed. The results show that under various rolling conditions, the equivalent concentration field in each layer of cartilage is increased to some extent compared with the steady concentration field. When the other variables are controlled, with the increase of compression, the equivalent concentration field of each unit of cartilage tissue increases relative to the steady concentration, and the maximum increase occurs when the roller rolls to about the middle position, and with the increase of rolling speed, For each layer of cartilage, the larger stress and strain occurred near the second layer.
【学位授予单位】：天津理工大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R318.01

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