Résumé :
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Satellite Cells (SCs) are defined by their anatomical location between the sarcolemma and the basal lamina of muscle fibres. Evidence suggests that only a subpopulation of SCs function as muscle stem cells. Here we demonstrate that the number of SCs per muscle fibre declines with age and is decreased in females compared to males. Single fibre suspension cultures show no difference in the kinetics of SC activation or the amount of self renewal. Together, these data suggest that changes in SC number do not reflect changes in SC function. Moreover, engraftments into pre irradiated muscles of mdx nude mice show no difference in the regenerative capacity of SCs obtained from male or female, pre weaned or adult donors. Despite variance in the total number of SCs, the number of 'stem' satellite cells remains constant. Current work aims to correlate SC marker expression with changes in the ratio of 'stem' to 'non stem' SCs to uncover possible stem SC isolation criteria.
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