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Extracellular matrix stiffness increases with age in tibialis anterior muscles of mice
Author(s) -
Kayupov Erdan,
Claflin Dennis R.,
Brooks Susan V.
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.1049.3
Subject(s) - extracellular matrix , tibialis anterior muscle , sarcomere , tendon , anatomy , chemistry , stiffness , myocyte , skeletal muscle , biology , endocrinology , materials science , composite material , biochemistry
Tibialis anterior (TA) tendons of mice exhibit a longitudinal gradient in mechanical stiffness, with stiffness increasing from the muscle interface to bone insertion. TA tendons stiffen with age, due primarily to dramatic increases near the muscle. The extracellular matrix (ECM) of tendon is mechanically coupled to the muscle ECM. Thus, the aim was to compare the mechanical properties of the ECM of muscles from young and old mice. We hypothesized that the ECM of muscles from old mice is stiffer than that of young mice. We determined passive length‐tension responses of individual permeabilized fibers and ECM‐containing bundles of permeabilized fibers from TA muscles of young (8 mo) and old (28 mo) mice. Tension was measured at sarcomere lengths (SL) ranging from 2.1μm to 3.1μm. No differences were seen between the stress responses of individual fibers from young and old mice for any SL tested. In contrast, the stress values produced by bundles from old mice were significantly higher (p<0.05) than those from young mice for all SL>2.5μm, reaching levels that were two‐fold higher at 3.1μm. We conclude that the stiffness of the ECM in TA muscles is greater in old mice than in young mice. Supported by NIH AR055624.