Document Detail


In situ mechanical properties of the chondrocyte cytoplasm and nucleus.
MedLine Citation:
PMID:  19261283     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The way in which the nucleus experiences mechanical forces has important implications for understanding mechanotransduction. Knowledge of nuclear material properties and, specifically, their relationship to the properties of the bulk cell can help determine if the nucleus directly experiences mechanical loads, or if it is a signal transduction mechanism secondary to cell membrane deformation that leads to altered gene expression. Prior work measuring nuclear material properties using micropipette aspiration suggests that the nucleus is substantially stiffer than the bulk cell [Guilak, F., Tedrow, J.R., Burgkart, R., 2000. Viscoelastic properties of the cell nucleus. Biochem. Biophys. Res. Commun. 269, 781-786], whereas recent work with unconfined compression of single chondrocytes showed a nearly one-to-one correlation between cellular and nuclear strains [Leipzig, N.D., Athanasiou, K.A., 2008. Static compression of single chondrocytes catabolically modifies single-cell gene expression. Biophys. J. 94, 2412-2422]. In this study, a linearly elastic finite element model of the cell with a nuclear inclusion was used to simulate the unconfined compression data. Cytoplasmic and nuclear stiffnesses were varied from 1 to 7 kPa for several combinations of cytoplasmic and nuclear Poisson's ratios. It was found that the experimental data were best fit when the ratio of cytoplasmic to nuclear stiffness was 1.4, and both cytoplasm and nucleus were modeled as incompressible. The cytoplasmic to nuclear stiffness ratio is significantly lower than prior reports for isolated nuclei. These results suggest that the nucleus may behave mechanically different in situ than when isolated.
Authors:
Gidon Ofek; Roman M Natoli; Kyriacos A Athanasiou
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural     Date:  2009-03-03
Journal Detail:
Title:  Journal of biomechanics     Volume:  42     ISSN:  1873-2380     ISO Abbreviation:  J Biomech     Publication Date:  2009 May 
Date Detail:
Created Date:  2009-04-21     Completed Date:  2009-06-17     Revised Date:  2011-05-02    
Medline Journal Info:
Nlm Unique ID:  0157375     Medline TA:  J Biomech     Country:  United States    
Other Details:
Languages:  eng     Pagination:  873-7     Citation Subset:  IM    
Affiliation:
Department of Bioengineering, Rice University, 6100 Main Street, Keck Hall Suite 116, Houston, TX 77005, USA.
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MeSH Terms
Descriptor/Qualifier:
Cell Nucleus*
Chondrocytes*
Cytoplasm*
Finite Element Analysis
Stress, Mechanical
Grant Support
ID/Acronym/Agency:
5R90DK71504-03/DK/NIDDK NIH HHS; 5T90DK70121-03/DK/NIDDK NIH HHS; R90 DK071504-03/DK/NIDDK NIH HHS; T90 DK070121-03/DK/NIDDK NIH HHS
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