Changes in diaphragm muscle collagen gene expression after acute unilateral denervation

L. E. Gosselin, G. C. Sieck, R. A. Aleff, D. A. Martinez, A. C. Vailas

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

The purpose of the present study was to examine the effects of acute (3 days) unilateral diaphragm denervation (DNV) on 1) levels of α1(I) and α1(III) procollagen mRNA; 2) collagen concentration [hydroxyproline (HYP)]; 3) amount of the nonreducible collagen cross-link hydroxylysylpyridinoline (HP); and 4) the passive force-length relationship of the muscle. The levels of α1(I) and α1(III) procollagen mRNA, HYP concentration, and amount of HP were measured in muscle segments from the midcostal region of DNV and intact (INT) hemidiaphragms of adult male Fischer 344 rats (250-300 g). The in vitro passive force-length relationship of DNV and INT hemidiaphragm was determined by lengthening and shortening the diaphragm muscle segments from 85 to 115% of optimal length at a constant velocity (0.6 optimal length/s). Three days after DNV, the level of α1(I) procollagen mRNA was increased over 15-fold in the DNV hemidiaphragm compared with INT (P < 0.05), whereas the level of α1(III) procollagen mRNA was increased by approximately sixfold in the DNV hemidiaphragm compared with INT (P < 0.05). Collagen (HYP) concentration did not differ between groups, averaging 8.7 and 8.9 μg/mg dry wt for the DNV and INT hemidiaphragms, respectively. In addition, there was no difference in the amount of the mature nonreducible collagen cross-link HP between the DNV and INT hemidiaphragms (0.66 vs. 0.76 mole HP/mole collagen, respectively). The amount of passive force developed during lengthening did not differ between DNV and INT hemidiaphragms. These data indicate that acute DNV of the hemidiaphragm is associated with an increase in the mRNA level of the two principal fibrillar collagen phenotypes in skeletal muscle. However, despite extensive muscle remodeling, the passive force-length relationship of the DNV hemidiaphragm is unaffected compared with the INT muscle.

Original languageEnglish (US)
Pages (from-to)1249-1254
Number of pages6
JournalJournal of applied physiology
Volume79
Issue number4
DOIs
StatePublished - Jan 1 1995

Keywords

  • connective tissue
  • extracellular matrix
  • plasticity
  • stretch

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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