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Complement activation promotes muscle inflammation during modified muscle useModified muscle use can result in muscle inflammation that is triggered by unidentified events. In the present investigation, we tested whether the activation of the complement system is a component of muscle inflammation that results from changes in muscle loading. Modified rat hindlimb muscle loading was achieved by removing weight-bearing from the hindlimbs for 10 days followed by reloading through normal ambulation. Experimental animals were injected with the recombinant, soluble complement receptor sCR1 to inhibit complement activation. Assays for complement C4 or factor B in sera showed that sCR1 produced large reductions in the capacity for activation of the complement system through both the classical and alternative pathways. Analysis of complement C4 concentration in serum in untreated animals showed that the classical pathway was activated during the first 2 hours of reloading. Analysis of factor B concentration in untreated animals showed activation of the alternative pathway at 6 hours of reloading. Administration of sCR1 significantly attenuated the invasion of neutrophils (-49%) and ED1(+) macrophages (-52%) that occurred in nontreated animals after 6 hours of reloading. The presence of sCR1 also reduced significantly the degree of edema by 22% as compared to untreated animals. Together, these data show that increased muscle loading activated the complement system which then briefly contributes to the early recruitment of inflammatory cells during modified muscle loading.
Document ID
20040141527
Document Type
Reprint (Version printed in journal)
Authors
Frenette, J. (University of California Los Angeles 90095-1527, United States)
Cai, B.
Tidball, J. G.
Date Acquired
August 22, 2013
Publication Date
June 1, 2000
Publication Information
Publication: American journal of pathology
Volume: 156
Issue: 6
ISSN: 0002-9440
Subject Category
Life Sciences (General)
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Musculoskeletal
Non-NASA Center
NASA Program Fundamental Space Biology