Document Detail

Diaphragm muscle weakness in mice is early-onset post myocardial infarction and associated with elevated protein oxidation.
MedLine Citation:
PMID:  25359720     Owner:  NLM     Status:  Publisher    
Heart failure induced by myocardial infarction (MI) causes diaphragm muscle weakness, with elevated oxidants implicated. We aimed to determine whether diaphragm muscle weakness is: 1) early-onset post MI (i.e., within the early left ventricular remodeling phase of 72 h); and 2) associated with elevated protein oxidation. Ligation of the left coronary artery to induce MI (n=10) or sham operation (n=10) was performed on C57BL6 mice. In vitro contractile function of diaphragm muscle fiber bundles was assessed 72 h later. Diaphragm mRNA and protein expression, enzyme activity, and individual carbonylated proteins (by 2D differential in-gel electrophoresis and mass spectrometry) were subsequently assessed. Infarct size averaged 57±1%. Maximal diaphragm function was reduced (p<0.01) by 20% post MI, with the force-frequency relationship depressed (p<0.01) between 80-300 Hz. The mRNA expression of inflammation, atrophy, and regulatory Ca(2+) proteins remained unchanged post MI, as did the protein expression of key contractile proteins. However, enzyme activity of the oxidative sources NADPH oxidase and xanthine oxidase were increased (p<0.01) by 45% and 33%, respectively. Compared to sham, a 57% and 45% increase (p<0.05) was observed in the carbonylation of sarcomeric actin and creatine kinase post MI, respectively. In conclusion, diaphragm muscle weakness was rapidly induced in mice during the early left ventricular remodeling phase of 72 h post MI, which was associated with increased oxidation of contractile and energetic proteins. Collectively, these findings suggest diaphragm muscle weakness may be early-onset in heart failure, which is likely mediated in part by post-translational oxidative modifications at the myofibrillar level.
T Scott Bowen; Norman Mangner; Sarah Werner; Stefanie Glaser; Yvonne Kullnick; Andrea Schrepper; Torsten Doenst; Andreas Oberbach; Axel Linke; Leif Steil; Gerhard Schuler; Volker Adams
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2014-10-30
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  -     ISSN:  1522-1601     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2014 Oct 
Date Detail:
Created Date:  2014-10-31     Completed Date:  -     Revised Date:  2014-11-2    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  -    
Other Details:
Languages:  ENG     Pagination:  jap.00756.2014     Citation Subset:  -    
Copyright Information:
Copyright © 2014, Journal of Applied Physiology.
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