Joshua A. Zimmermann^*, Melissa L. Knothe Tate^∗,†,‡

Molecular & Cellular Biomechanics, Vol.8, No.4, pp. 275-296, 2011, DOI:10.3970/mcb.2011.008.275

Abstract Shape and fate are intrinsic manifestations of form and function at the cell scale. Here we hypothesize that seeding density and protocol affect the form and function of live embryonic murine mesenchymal stem cells (MSCs) and their nuclei. First, the imperative for study of live cells was demonstrated in studies showing changes in cell nucleus shape that were attributable to fixation per se. Hence, we compared live cell and nuclear volume and shape between groups of a model MSC line (C3H10T1/2) seeded at, or proliferated from 5,000 cells/cm2 to one of three target densities to achieve targeted development contexts. Cell… More >

Ramana M. Pidaparti^∗,†, Kittisak Koombua^∗,‡

Molecular & Cellular Biomechanics, Vol.8, No.2, pp. 149-168, 2011, DOI:10.3970/mcb.2011.008.149

Abstract Better understanding of the stress/strain environment in airway tissues is very important in order to avoid lung injuries for patients undergoing mechanical ventilation for treatment of respiratory problems. Airway tissue strains responsible for stressing the lung's fiber network and rupturing the lung due to compliant airways are very difficult to measure experimentally. A computational model that incorporates the heterogeneity of the airways was developed to study the effects of airway tissue material properties on strain distributions within each layer of the airway wall. The geometry and boundary conditions of the tissue strain analysis were obtained from the organ-level analysis model.… More >

Min Zhang^∗, Fa-Ming Chen^†, Yong-Jin Chen^∗,‡, Shun Wu^∗, Xin Lv^∗, Rui-Ni Zhao^∗

Molecular & Cellular Biomechanics, Vol.8, No.1, pp. 43-60, 2011, DOI:10.3970/mcb.2011.008.043

Abstract To investigate the role of mechanical pressure on cartilage thickness and type II collagen synthesis, and the role of G protein in that process, in vitro organ culture of mandibular cartilage was adopted in this study. A hydraulic pressure-controlled cellular strain unit was used to apply hydrostatic pressurization to explant cultures. The explants were compressed by different pressure values (0 kPa, 100 kPa, and 300 kPa) after pretreatment with or without a selective and direct antagonist (NF023) for the G proteins. After 4, 8 and 12 h of cell culture under each pressure condition, histological sections of the explants were… More >

Guanbin Song^∗,†,‡, Qing Luo^*, Baiyao Xu^*, Yang Ju^†

Molecular & Cellular Biomechanics, Vol.7, No.3, pp. 165-174, 2010, DOI:10.3970/mcb.2010.007.165

Abstract It has been demonstrated that mechanical stimulation plays a vital role in regulating the proliferation and differentiation of stem cells. However, little is known about the effects of mechanical stress on tendon/ligament development from mesenchymal stem cells (MSCs). Here, using a custom-made cell-stretching device, we studied the effects of mechanical stretching on the cell morphology and mRNA expression of several key genes modulating tendon/ligament genesis. We demonstrate that bone-marrow-derived rat MSCs (rMSCs), when subjected to cyclic uniaxial stretching, express obvious detectable mRNAs for tenascin C and scleraxis, a unique maker of tendon/ligament formation, and significantly increased levels of type I… More >

Yequan Wang^*, Li Yang^*, Jin Zhang^*, Ruyue Xue^*, Zhenyu Tang^*, Wei Huang^†, Dianming Jiang^†, Xinyan Tang^*, Peter Chen^‡, KL Paul Sung^{∗,‡,§,¶}

Molecular & Cellular Biomechanics, Vol.7, No.2, pp. 105-114, 2010, DOI:10.3970/mcb.2010.007.105

Abstract The anterior cruciate ligament, posterior cruciate ligament, cartilage and meniscus in human knee joint have poor healing ability. Accumulation of MMPs in the joint fluids due to knee injury has been considered as the main reason. Our previous experiments showed that synovium may be the major regulator of MMPs in joint cavity after injury. In this paper, we used human synoviocytes harvested from synovium to determine whether mechanical injury and inflammatory factors will induce MMP-2 production in synoviocytes. With zymography, we found that mechanical compression increased the MMP-2 production by 23% under 6% compressions, 61% under 12% compression and 109%… More >

Xituan Shang^*, Michael R. T. Yen^1,†, M. Waleed Gaber^‡

Molecular & Cellular Biomechanics, Vol.7, No.2, pp. 93-104, 2010, DOI:10.3970/mcb.2010.007.093

Abstract The objective of this research is to conduct mechanical property studies of skin from two individual but potentially connected aspects. One is to determine the mechanical properties of the skin experimentally by biaxial tests, and the other is to use the finite element method to model the skin properties. Dynamic biaxial tests were performed on 16 pieces of abdominal skin specimen from rats. Typical biaxial stress-strain responses show that skin possesses anisotropy, nonlinearity and hysteresis. To describe the stress-strain relationship in forms of strain energy function, the material constants of each specimen were obtained and the results show a high… More >

Q Wang^*, YP Zheng^∗,†, HJ Niu^∗,‡

Molecular & Cellular Biomechanics, Vol.7, No.1, pp. 45-58, 2010, DOI:10.3970/mcb.2010.007.045

Abstract This study aims to obtain osmosis-induced swelling strains of normal and proteoglycan (PG) depleted articular cartilage using an ultrasound system and to investigate the changes in its mechanical properties due to the PG depletion using a layered triphasic model. The swelling strains of 20 cylindrical cartilage-bone samples collected from different bovine patellae were induced by decreasing the concentration of bath saline and monitored by the ultrasound system. The samples were subsequently digested by a trypsin solution for approximately 20 min to deplete proteoglycans, and the swelling behaviors of the digested samples were measured again. The bi-layered triphasic model proposed in… More >

Ning Wang^*

Molecular & Cellular Biomechanics, Vol.7, No.1, pp. 33-44, 2010, DOI:10.3970/mcb.2010.007.033

Abstract Professor Y.C. Fung has shown that living tissues remodel extensively in response to mechanical forces such as blood pressure variations. At the cellular level, those mechanical perturbations must be perceived by individual cells. However, mechanisms of mechanochemical transduction in living cells remain a central challenge to cell biologists. Contrary to predictions by existing models of living cells, we reported previously that a local stress, applied via integrin receptors, is propagated to remote sites in the cytoplasm and is concentrated at discrete foci. Here we report that these foci of strains and stresses in the cytoplasm correspond to local peak deformation… More >

He Gong^∗,†, Ming Zhang^‡

Molecular & Cellular Biomechanics, Vol.7, No.1, pp. 1-12, 2010, DOI:10.3970/mcb.2010.007.001

Abstract In mechanical disuse conditions associated with immobilization and microgravity in spaceflight, cortical endosteal surface moved outward with periosteal surface moving slightly or unchanged, resulting in reduction of cortical thickness. Reduced thickness of the shaft cortex of long bone can be considered as an independent predictor of fractures. Accordingly, it is important to study the remodeling process at cortical endosteal surface. This paper presents a computer simulation of cortical endosteal remodeling induced by mechanical disuse at the Basic Multicellular Units level with cortical thickness as controlling variables. The remodeling analysis was performed on a representative rectangular slice of the cross section… More >

Masanori Kobayashi, Myron Spector

Molecular & Cellular Biomechanics, Vol.6, No.4, pp. 217-228, 2009, DOI:10.3970/mcb.2009.006.217

Abstract In order to achieve successful wound repair by regenerative tissue engineering using mesenchymal stem cells (MSCs), it is important to understand the response of stem cells in the scaffold matrix to mechanical stress.
To investigate the clinical effects of mechanical stress on the behavior of cells in scaffolds, bone marrow-derived mesenchymal stem cells (MSCs) were grown on a type-I collagen-glycosaminoglycan (GAG) scaffold matrix for one week under cyclic stretching loading conditions.
The porous collagen-GAG scaffold matrix for skin wound repair was prepared, the harvested canine MSCs were seeded on the scaffold, and cultured under three kinds of cyclic… More >