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In situ cell nucleus deformation in tendons under tensile load; a morphological analysis using confocal laser microscopy
Author(s) -
Arnoczky Steven P.,
Lavagnino Michael,
Whallon Joanne H.,
Hoonjan Amardeep
Publication year - 2002
Publication title -
journal of orthopaedic research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.041
H-Index - 155
eISSN - 1554-527X
pISSN - 0736-0266
DOI - 10.1016/s0736-0266(01)00080-8
Subject(s) - in situ , confocal laser scanning microscopy , confocal , nucleus , confocal microscopy , materials science , microscopy , deformation (meteorology) , laser , ultimate tensile strength , composite material , optics , biophysics , chemistry , biology , physics , microbiology and biotechnology , organic chemistry
Cell and cell nucleus deformations have been implicated in the mechanotransduction of mechanical loads acting on tissues. While in situ cell nucleus deformation in response to increasing tissue strains has been examined in articular cartilage this phenomenon has not been investigated in tendons. To examine in situ cell nuclei deformation in tendons undergoing tensile strain rat tail tendons were harvested from adult Sprague–Dawley rats and stained with acridine orange to highlight the cell nuclei. The tendons were mounted on a custom‐designed, low‐load, tensile testing device affixed to the mechanical stage of a confocal laser microscope. Cells within the tendons were isolated for analysis. Images of individual cells were captured at 0% strain as well as sequentially at 2%, 4% and 6% grip‐to‐grip tendon strain. Digital images of the cell nuclei were then measured in the x (length) and y (height) axis and deformation expressed as a percentage of cell nuclei strain. In addition, centroid‐to‐centroid distances of adjacent cell nuclei within each image were measured and used to calculate local tissue strain. There was a weak ( r 2 = 0.34) but significant ( p < 0.01) correlation between local tissue strain and cell nucleus strain in the x axis. The results of this study support the hypothesis that in situ cell nucleus deformation does occur during tensile loading of tendons. This deformation may play a significant role in the mechanical signal transduction pathway of this tissue. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.