Titre :
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Size determination and quantification of sarcolemmal disruptions in muscle in an ageing dyferlin deficient mouse model (poster) : Actes de colloque : 4ème colloque international de Myologie - 9-13 mai 2011; Lille, France
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contenu dans :
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Auteurs :
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Petiot J ;
de Dreuzy E ;
Richard I ;
Stockholm D
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Type de document :
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Article
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Année de publication :
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2011
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Pages :
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p 118
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Langues:
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Anglais
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Mots-clés :
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colloque
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Résumé :
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Dysferlin deficient muscle fibers have been shown to be defective in membrane repair after a laser wounding damage of the sarcolemme. In vivo, sarcolemmal membrane disruption can either lead to fiber necrosis or repair but little is known about the size and the kinetics of apparition of the tears. In this purpose, we have submitted dysferlin-deficient Dysfprmd mice to a running exercise protocol -known to involve lengthening contractions- to exacerbate the sarcolemmal damage phenotype in order to investigate several aspects underlying membrane tears apparition.To estimate the extent of sarcolemmal damage, we used a size exclusion strategy based on the penetration into the damaged fibers of different sized circulating fluorescent dextrans. We explored a variety of labelled dextrans from 3 to 70 kDa that are injected intraperitonealy in mice before exercise. Muscles are dissected immedialtely after the running protocol. Positive dextrans-labelled fibers are counted on five different hindlimb muscles by large-field morphometry analysis in fluorescence. Our results allowed us to estimate membrane rips to be under 10?m all over the ageing process and on whatever analysed muscle. Besides, we found an overall increase of tears frequency in exercised muscles and particularly in proximal muscles, which is in accordance with previous characterisation of damage specificity in this model. We further investigate any muscle tissue structure evolution with the age. It revealed that muscle tissue composition is subjected to a huge increase of fat proportion involving a great loss of muscle fibers susceptible to damage. These data help to clarify the size of membrane tears and may be useful for the understanding of the mechanisms of membrane repair in the context of dysferlinopathy.
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