Mechanical loading regulates tenascin-C expression in the osteotendinous junction

Tero A.H. Järvinen, Laszlo Jozsa, Pekka Kannus, Teppo L.N. Järvinen, Martti Kvist, Timo Hurme, Jorma Isola, Hannu Kalimo, Markku Järvinen

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Abstract

Elastic extracellular matrix protein tenascin-C (TN) has very restricted expression in normal tissues, but is expressed in large quantities during embryogenesis and hyperplastic processes. To examine the importance of mechanical stress on the regulation of TN expression in vivo, the effects of various mechanical loading states (immobilization and three forms of subsequent remobilization) on the expression of TN were studied immunohistochemically at the bone-tendon attachment of the rat quadriceps muscle. This osteotendinous junction (OTJ) was selected as study site, since it receives its mechanical stimuli only from muscle contracting activity, which is easy to block by cast immobilization. TN was expressed abundantly in the normal OTJ. Following the removal of the mechanical stress from the junction by cast-immobilization of three weeks, the immunoreactivity of TN was almost completely absent. Normal mechanical stress in the form of free remobilization of eight weeks (free cage activity) resulted in a slight increase in TN expression, but could not restore the expression of TN to the level of the healthy contralateral leg. After the application of the increased mechanical stress (intensified remobilization of the eight weeks by low- or high-intensity treadmill running), the distribution and immunoreactivity of TN reached the level of the healthy contralateral limb in the low-intensity running group or even exceeded that in the high-intensity running group. High TN expression was seen around the chondrocytes and fibroblasts of the OTJ as well as around the collagen fibers of the tendon belly. We conclusively show that mechanical strain regulates the expression of TN in vivo and propose that mechanical stress is a major regulator of TN expression in fibroblasts and chondrocytes. This may be an important aspect of the regulation of TN expression during embryogenesis, tendon degeneration, wound healing, bone formation, and in the other normal or regenerative morphogenetic processes TN is postulated to take part in.

Original languageEnglish
Pages (from-to)3157-3166
Number of pages10
JournalJournal of cell science
Volume112
Issue number18
Publication statusPublished - Oct 14 1999

Keywords

  • Adhesion
  • Elastic
  • Extracellular matrix
  • Immobilization
  • Immunohistochemistry
  • Mechanical strain
  • Remobilization
  • Tenascin-C
  • Tensile

ASJC Scopus subject areas

  • Cell Biology

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  • Cite this

    Järvinen, T. A. H., Jozsa, L., Kannus, P., Järvinen, T. L. N., Kvist, M., Hurme, T., Isola, J., Kalimo, H., & Järvinen, M. (1999). Mechanical loading regulates tenascin-C expression in the osteotendinous junction. Journal of cell science, 112(18), 3157-3166.