Stretch-induced force deficits in murine extensor digitorum longus muscles after cardiotoxin injection.
A leftward shift in a muscle's length-tension relationship is thought to impair myofilament overlap. We hypothesized that left-shifted muscles would incur greater eccentric contraction-induced damage compared to controls. We evaluated contractile properties and force deficits in regenerating murine extensor digitorum longus (EDL) muscles 7, 14, and 21 days after cardiotoxin (CTX) injection. Specific tension recovered to control values by 21 days. CTX-injected muscles demonstrated left-shifted length-tension curves and incurred greater contraction-induced force deficits than controls (P < 0.001) on day 7. We speculate that increased contraction-induced damage in 7-day CTX-injected muscles results from changes in myofilament overlap that occurs during early regeneration.
Markert
Chad
C
Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, USA.
Petroski
Gregory F
GF
Childers
Charles K
CK
McDonald
Kerry S
KS
Childers
Martin K
MK
D008841:Actin Cytoskeleton / Q000187:drug effects / Q000502:physiology; D000818:Animals; D004179:Cobra Cardiotoxin Proteins / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009119:Muscle Contraction / Q000187:drug effects* / Q000502:physiology; D018482:Muscle, Skeletal / Q000187:drug effects / Q000473:pathology / Q000502:physiology*; D009336:Necrosis / Q000473:pathology; D013997:Time Factors
D004179:Cobra Cardiotoxin Proteins