Myonuclear addition is associated with sex-specific fiber hypertrophy and occurs in relation to fiber perimeter not cross-sectional area
Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
Dokumenter
- Moesgaard et al_Journal of Applied Physiology_2022_(JAPPL-00235_2022R2)_(Accepted manuscript)
Accepteret manuskript, 4,71 MB, PDF-dokument
It is unclear whether resistance training-induced myofiber hypertrophy is affected by sex, and whether myonuclear addition occurs in relation to the myonuclear domain and can contribute to explaining a potential sex-specific hypertrophic response. This study investigated the effect of 8 weeks of resistance training on myofiber hypertrophy and myonuclear addition in 12 males (28±7 years; mean±SD) and 12 females (27±7 years). Muscle biopsies were collected from m. vastus lateralis before and after the training intervention and analyzed by immunohistochemistry for fiber type and size, satellite cells, and myonuclei. Hypertrophy of type I fibers was greater in males than females (P < 0.05), whereas hypertrophy of type II fibers was similar between sexes (P = 0.158‒0.419). Expansion of the satellite cell pool (P = 0.132‒0.667) and myonuclear addition (P=0.064‒0.228) did not differ significantly between sexes, irrespective of myofiber type. However, when individual responses to resistance training were assessed, myonuclear addition was strongly correlated with fiber hypertrophy (r = 0.68‒0.85, P < 0.001). While myofiber hypertrophy was accompanied by an increase in myonuclear domain (P < 0.05), fiber perimeter per myonucleus remained constant throughout the study (P = 0.096‒0.666). These findings indicate that myonuclear addition occurs in relation to the fiber perimeter per myonucleus, not the myonuclear domain, and has a substantial role in muscle hypertrophy, but does not fully explain greater hypertrophy of type I fibers in males than females.
Originalsprog | Engelsk |
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Tidsskrift | Journal of Applied Physiology |
Vol/bind | 133 |
Udgave nummer | 3 |
Sider (fra-til) | 732-741 |
Antal sider | 10 |
ISSN | 8750-7587 |
DOI | |
Status | Udgivet - 2022 |
Bibliografisk note
CURIS 2022 NEXS 221
- Det Natur- og Biovidenskabelige Fakultet
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