Document Detail

High intensity exercise increases expression of matrix metalloproteinases in fast skeletal muscle fibres.
MedLine Citation:
PMID:  15833756     Owner:  NLM     Status:  MEDLINE    
Metalloproteinases (MMPs) are proteolytic enzymes that function in the extracellular matrix to degrade connective tissues. While it is clear that exercise-induced injury in skeletal muscle promotes increased expression of MMPs, the relationship between exercise intensity and expression of MMPs in muscles is unknown. These experiments tested the hypothesis that exercise-induced expression of matrix metalloproteinases (MMP-2 and MMP-9) is dose-dependent such that high-intensity endurance exercise increases MMP expression whereas low-intensity endurance exercise will not promote MMP expression in skeletal muscles. Female rats (4 months old) completed 2 weeks of treadmill running at either low (18 m min(-1); approximately 50% maximum oxygen consumption rate ) or high intensity (32 m min(-1); approximately 70% ; up to 50 min day(-1)). Non-running, sedentary animals served as controls. Muscle mRNA and protein levels of MMP-2 and MMP-9 were assessed in gastrocnemius, quadriceps and soleus muscles by reverse transcriptase-polymerase chain reaction and Western blotting, respectively. Results indicate that exercise did not alter MMP-9 in any of these skeletal muscles. Further, our data reveal that low-intensity exercise did not alter the expression of MMP-2 in any of the muscles investigated. In contrast, high-intensity exercise increased both mRNA and protein levels of MMP-2 in skeletal muscles containing a high percentage of fast type II fibres (i.e. gastronemius and superficial quadriceps). These results support the hypothesis that high-intensity exercise is required to promote the expression of MMP-2 in skeletal muscles and that the influence of exercise on MMP-2 expression is dominant in muscles containing a high percentage of fast fibres.
Eli Carmeli; Miri Moas; Shannon Lennon; Scott K Powers
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2005-04-15
Journal Detail:
Title:  Experimental physiology     Volume:  90     ISSN:  0958-0670     ISO Abbreviation:  Exp. Physiol.     Publication Date:  2005 Jul 
Date Detail:
Created Date:  2005-07-04     Completed Date:  2005-09-21     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  9002940     Medline TA:  Exp Physiol     Country:  England    
Other Details:
Languages:  eng     Pagination:  613-9     Citation Subset:  IM    
Department of Physical Therapy, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel.
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MeSH Terms
Blotting, Western
Body Weight / physiology
Electrophoresis, Polyacrylamide Gel
Matrix Metalloproteinase 2 / biosynthesis
Matrix Metalloproteinase 9 / biosynthesis
Matrix Metalloproteinases / biosynthesis*
Muscle Fibers, Fast-Twitch / enzymology*
Muscle Fibers, Skeletal / enzymology*
Organ Size / physiology
Oxygen Consumption / physiology
Physical Conditioning, Animal / physiology*
Physical Exertion / physiology*
RNA, Messenger / biosynthesis
Rats, Sprague-Dawley
Reverse Transcriptase Polymerase Chain Reaction
Reg. No./Substance:
0/RNA, Messenger; EC 3.4.24.-/Matrix Metalloproteinases; EC Metalloproteinase 2; EC Metalloproteinase 9

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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