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1.
The aim of this study was to test the differentiative effects of osteoblasts after treatment with a static magnetic field (SMF). MG63 osteoblast-like cells were exposed to a 0.4-T SMF. The differentiation markers were assessed by observing the changes in alkaline phosphatase activity and electron microscopy images. Membrane fluidity was used to evaluate alterations in the biophysical properties of the cellular membranes after the SMF simulation. Our results show that SMF exposure increases alkaline phosphatase activity and extracellular matrix release in MG63 cells. On the other hand, MG63 cells exposed to a 0.4-T SMF exhibited a significant increase in fluorescence anisotropy at 6 h, with a significant reduction in the proliferation effects of growth factors noted at 24 h. Based on these findings, the authors suggest that one of the possible mechanisms that SMF affects osteoblastic maturation is by increasing the membrane rigidity and reducing the proliferation-promoting effects of growth factors at the membrane domain.  相似文献
2.
细胞-分子生物力学研究进展   总被引:2,自引:0,他引:2       下载免费PDF全文
细胞-分子生物力学作为生物力学的重要分支,近三十年来在力学-生物学、力学-化学耦合等方面取得了重大进展,已成为生物力学乃至生物医学工程领域最活跃的领域,并对生物学、医学乃至农业产生了重要影响。本文介绍了细胞-分子生物力学研究领域的基本概念、科学问题和研究方法,并讨论了尚待解决的问题。  相似文献
3.
The behavior of normal adherent cells is influenced by the stiffness of the substrate they are anchored to. Cells are able to detect substrate mechanical properties by actively generating contractile forces and use this information to migrate and proliferate. In particular, the speed and direction of cell crawling, as well as the rate of cell proliferation, vary with the substrate compliance and prestrain. In this work, we present an active mechanosensing model based on an extension of the classical Hill’s model for skeletal muscle behavior. We also propose a thermodynamical approach to model cell migration regulated by mechanical stimuli and a proliferation theory also depending on the mechanical environment. These contributions give rise to a conceptually simple mathematical formulation with a straightforward and inexpensive computational implementation, yielding results consistent with numerous experiments. The model can be a useful tool for practical applications in biology and medicine in situations where cell–substrate interaction as well as substrate mechanical behavior play an important role, such as the design of tissue engineering applications.  相似文献
4.
心血管生物力学研究的新进展   总被引:1,自引:0,他引:1       下载免费PDF全文
心血管生物力学研究领域最重要的新进展有两个方面:一是心血管力学生物学研究。阐明力学因素如何产生生物学效应而导致血管重建,研究心血管信号转导通路和力学调控途径,从细胞分子水平深入了解心血管活动和疾病发生的本质;二是以临床影像为基础的心血管生物力学建模与个体化手术设计研究。应用流体力学理论,结合医学影像和先进的流场测试技术,进行心血管建模与定量分析,研究心血管功能新的无创检测技术和个体化治疗体系设计,为心血管病的诊断、治疗和预警提供生物力学的解决方案。本期"心血管生物力学"专刊发表了7篇国内同行的相关研究论文。这些论文的内容涵盖了血管壁细胞力学生物学和紧密结合临床的心血管生物力学建模研究,反映了我国心血管生物力学研究的一些新进展。  相似文献
5.
Bone regeneration is a common biological process occurring, for example, during fracture healing or osseo-integration of prostheses. Computer simulation of bone regeneration is difficult to carry out because it is a complex sequence of cell-mediated processes regulated by mechanobiological stimuli. An algorithm to predict the time-course of intramembranous and endochondral ossification has been developed. The algorithm assumes that there are precursor cells in the undifferentiated tissue and that these cells differentiate into either fibroblasts (to form fibrous connective tissue), chondrocytes (to form cartilaginous tissue) or osteoblasts (to form bone), based on a combination of biophysical stimuli derived from strain in the collagenous matrix and flow of the interstitial fluid. Both these stimuli are known to deform the precursor cells, and the authors hypothesise that this causes activation of cell differentiation pathways. The observation that precursor cells take time to spread throughout the fracture callus has been included in the algorithm. The algorithm was tested in an investigation of the fracture healing of a long bone using an axisymmetric finite element model. The spatio-temporal sequence of tissue phenotypes that appear in the course of fracture healing was successfully simulated. Furthermore, the origin of the precursor cells (either surrounding muscle, bone marrow or periosteum) was predicted to have a fundamental effect on the healing pattern and on the rate of reduction of the interfragmentary strain (IFS). The initial IFS=0.15 drops to 0.01 within seven iterations if cells originated from the surrounding soft tissue, but took more than 50% longer if cells originated in the inner cambium layer of the periosteum, and four times longer if precursor cells originated from the bone marrow only.  相似文献
6.
The critical importance of mechanical signals to the health and maintenance of articular cartilage has been well demonstrated. Tissue engineers have taken a cue from normal cartilage physiology and incorporated the use of mechanical stimulation into their attempts to engineer functional cartilage. However, the specific types of mechanical stimulation that are most beneficial, and the mechanisms that allow a chondrocyte to perceive and respond to those forces, have yet to be elucidated. To develop a better understanding of these processes, it is necessary to examine the mechanical behavior of the single chondrocyte. This paper reviews salient topics related to chondrocyte biomechanics and mechanotransduction, and attempts to put this information into a context both appropriate and useful to cartilage tissue engineering. It also describes the directions this exciting field is taking, and lays out a vision for future studies that could have a significant impact on our understanding of cartilage health and disease. © 2003 Biomedical Engineering Society.  相似文献
7.
Many morphological changes occur during development of the proximal femur. The anteversion angle is a measure of the rotation of the neck of the femur around the diaphysis. In normal development anteversion is 30 degrees at birth and decreases to 15 degrees by skeletal maturity. In children with cerebral palsy (CP) anteversion often increases slightly and remains high throughout development. Previous models have proposed that cyclic hydrostatic stress decreases the growth rate while cyclic octahedral shear stress increases the growth rate. In this study we also examine changes in the growth direction caused by deformation of the developing cartilage. Using these mechanobiological principles we considered the influence of mechanical loads on the formation of the anteversion angle in normal and CP development. Loads were applied to a three-dimensional finite element model of the proximal femur. From the resulting stresses and deformations at the growth front we calculated the growth rate and growth direction and simulated the progression of the growth front over 6 months. The model predicted a decrease in anteversion angle (-2 degrees over 6 months) under normal-loading conditions, and an increase in anteversion (+ 1 degrees over 6 months) under CP-loading conditions. These results compare well with observations during skeletalgenesis, in which the anteversion angle decreases rapidly in the first few years of normal growth and may increase in children with CP.  相似文献
8.
In most cell culture studies, cells are grown on smooth culture surfaces. Using microfabrication technology, we have developed microgrooved silicone surfaces to grow cells and subject them to repetitive mechanical stretching. When human patellar tendon fibroblasts were plated on these microgrooved surfaces, the cells had an elongated shape and underwent cyclic uniaxial stretching parallel to their long axes, all of which closely mimic conditions of tendon fibroblasts in vivo. Also, when fibroblasts were grown on microgrooves oriented at 45 and 90 degrees with respect to stretching direction, they did not change alignment or shape under cyclic mechanical stretching. Furthermore, compared to nonstretched cells, 8% cyclic stretching of tendon fibroblasts oriented at 0 (i.e., parallel to stretching direction), 45, and 90 degrees was found to increase -SMA protein expression level by 46, 31, and 14%, respectively. In addition, 8% cyclic stretching tendon fibroblasts for 4 and 8 h oriented parallel to stretching direction increased -SMA protein expression level by 25 and 57%, respectively. Thus, the results of this study showed that -SMA protein expression levels of tendon fibroblasts depend on cell orientation with respect to stretching direction and stretching duration. We suggest that microgrooved silicone substrates can be used to study biological responses of tendon or ligament fibroblasts to repetitive mechanical stretching conditions in a more controlled manner.  相似文献
9.
Interstitial fluid flow, critical for macromolecular transport, was recently shown to drive fibroblast differentiation and perpendicular cell and matrix alignment in 3D collagen cultures. Here we explore the mechanisms underlying this flow-induced cell and collagen alignment. Cell and matrix alignment was assessed from 3D confocal reflectance stacks using a Fast Fourier Transform method. We found that human dermal and lung fibroblasts align perpendicular to flow in the range of 5–13 μm/s (0.1–0.3 dyn/cm2) in collagen; however, neither cells nor matrix fibers align in fibrin cultures, which unlike collagen, is covalently cross-linked and generally degraded by cell fibrinolysis. We also found that even acellular collagen matrices align weakly upon exposure to flow. Matrix alignment begins within 12 h of flow onset and continues, along with cell alignment, over 48 h. Together, these data suggest that interstitial flow first induces collagen fiber alignment, providing contact guidance for the cells to orient along the aligned matrix; later, the aligned cells further remodel and align their surrounding matrix fibers. These findings help elucidate the effects of interstitial flow on cells in matrices and have relevance physiologically in tissue remodeling and in tissue engineering applications.  相似文献
10.
力学生物学研究力学环境对生物体健康、疾病或损伤的影响,研究生物体的力学信号感受和响应机制,阐明机体的力学过程与生物学过程如生长、重建、适应性变化和修复等之间的相互关系,从而发展有疗效的或有诊断意义的新技术。本刊报道了国内心血管力学生物学研究的一些新进展。心血管力学生物学探讨血管的“应力-生长”关系,阐明力学因素如何产生生物学效应而导致血管重建;基于心血管系统建模与定量分析,建立精确规范的心血管功能新的无创检测和分析技术。这些研究不仅对于揭示正常血液循环的生物力学机理,认识血管生长、衰老的自然规律,而且对于阐明血管疾病的发病机理以及提供诊断、治疗的一些基本原理包括心血管新型药物和新技术的研发都将有重要的理论和实际意义。  相似文献
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