Age-related changes in structure and extracellular matrix protein expression levels in rat tendons

Tatiana Y. Kostrominova, Susan V. Brooks

Research output: Contribution to journalArticle

50 Scopus citations


The musculoskeletal system (muscle-tendon-bone) demonstrates numerous age-related changes, with modifications in tendons the least well studied, although increased predisposition to tendinopathy and rupture have been reported. In order to gain insights into the basis of age-associated increase in tendon injuries, we compared Achilles and tibialis anterior tendons and myotendinous junctions (MTJs) from 3- to 5- and 22-to 25-month-old rats for underlying structure and composition. Significant decreases were observed by qRTPCR for collagen I, III, and V mRNA expression in tendons of old rats, but immunostaining detected no apparent differences in collagen I and V expression on the protein level. Tendons of old compared with youngrats had decreased mRNA expression levels of proteoglycan 4 (PRG4) and elastin (Eln), but no differences in the mRNA expression of connective tissue growth factor, TGF-beta 1, or stromal cell-derived factor 1. For PRG4, immunostaining showed good correlation with qRT-PCR results. This is the first study to show reductions in PRG4 in tendons and MTJs of old rats. Decreased PRG4 expression in tendons could result in increased tendon stiffness and may be associated with decreased activity in the elderly. The diminished collagen mRNA expression in combination with decreased PRG4 and Eln mRNA expression may be associated with increased risk of tendon injury with aging.

Original languageEnglish (US)
Pages (from-to)2203-2214
Number of pages12
Issue number6
StatePublished - Dec 1 2013


  • Aging
  • Elastin
  • Myotendinous junctions
  • PRG4
  • Tendon

ASJC Scopus subject areas

  • Aging
  • Geriatrics and Gerontology

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