Abstract
The continuity of the tendon–myofibre–tendon units disrupted by shearing injury must
be re-established during regeneration. We have previously demonstrated in freely moving
rats that transected myofibres reinforce their lateral integrin-mediated adhesion,
with the maximum around days 5–7. After day 14, most integrin molecules are redistributed
to the newly formed myotendinous junctions, by which the ends of regenerating myofibres
attach to the scar between the stumps. Here, we analyzed the effects of mechanical
stress (free and forced mobilization vs. immobilization and denervation separately
and in combination) on the expression of α7 integrin and merosin in regenerating myofibres
using quantitative in situ hybridization and immunohistochemistry. In all groups,
α7 integrin expression was upregulated at mRNA level, whereas increased protein accumulation
in lateral sarcolemma occurred only in the mobilized groups. The accumulation of merosin
was not affected by the stress level. The results demonstrate that active mechanical
stress reinforces early lateral integrin-mediated adhesion; molecules may at the same
time mediate signals from matrix to cells for adaptation to the altered biomechanical
status.
Keywords
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Article info
Publication history
Accepted:
September 13,
2000
Received in revised form:
September 4,
2000
Received:
April 19,
2000
Identification
Copyright
© 2001 Elsevier Science B.V. Published by Elsevier Inc. All rights reserved.
