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Early accentuated muscle hypertrophy is strongly associated with myonuclear accretion.
Lundberg, Tommy R; Martínez-Aranda, Luis Manuel; Sanz, Gema; Hansson, Björn; von Walden, Ferdinand; Tesch, Per A; Fernandez-Gonzalo, Rodrigo.
Afiliación
  • Lundberg TR; Division of Clinical Physiology, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden.
  • Martínez-Aranda LM; Unit of Clinical Physiology, Karolinska University Hospital, Stockholm, Sweden.
  • Sanz G; Division of Clinical Physiology, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden.
  • Hansson B; Unit of Clinical Physiology, Karolinska University Hospital, Stockholm, Sweden.
  • von Walden F; Faculty of Sport, Neuroscience of Human Movement Research Group (Neuromove), Catholic University of San Antonio, Murcia, Spain.
  • Tesch PA; Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.
  • Fernandez-Gonzalo R; Gnomics, Murcia, Spain.
Am J Physiol Regul Integr Comp Physiol ; 319(1): R50-R58, 2020 07 01.
Article en En | MEDLINE | ID: mdl-32432913
The current study explored whether the marked hypertrophic response noted with a short-term unilateral concurrent exercise paradigm was associated with more prominent changes in myonuclei accretion, ribosome biogenesis, and capillarization compared with resistance exercise alone (RE). Ten men (age 25 ± 4 yr) performed aerobic and resistance exercise (AE + RE) for one leg while the other leg did RE. Muscle biopsies were obtained before and after 5 wk of training and subjected to fiber-type specific immunohistochemical analysis, and quantification of total RNA content and mRNA/rRNA transcript abundance. Type II fiber cross-sectional area (CSA) increased with both AE + RE (22%) and RE (16%), while type I fiber CSA increased mainly with AE + RE (16%). The change score tended to differ between legs for type I CSA (P = 0.099), and the increase in smallest fiber diameter was greater in AE + RE than RE (P = 0.029). The number of nuclei per fiber increased after AE + RE in both fiber types, and this increase was greater (P = 0.027) than after RE. A strong correlation was observed between changes in number of nuclei per fiber and fiber CSA in both fiber types, for both AE + RE and RE (r > 0.8, P < 0.004). RNA content increased after AE + RE (24%, P = 0.019), but the change-scores did not differ across legs. The capillary variables generally increased in both fiber types, with no difference across legs. In conclusion, the accentuated hypertrophic response to AE + RE was associated with more pronounced myonuclear accretion, which was strongly correlated with the degree of fiber hypertrophy. This suggests that myonuclear accretion could play a role in facilitating muscle hypertrophy also during very short training periods.
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Ejercicio Físico / Núcleo Celular / Músculo Esquelético Límite: Adult / Humans / Male Idioma: En Revista: Am J Physiol Regul Integr Comp Physiol Asunto de la revista: FISIOLOGIA Año: 2020 Tipo del documento: Article País de afiliación: Suecia Pais de publicación: Estados Unidos
Texto completo
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Ejercicio Físico / Núcleo Celular / Músculo Esquelético Límite: Adult / Humans / Male Idioma: En Revista: Am J Physiol Regul Integr Comp Physiol Asunto de la revista: FISIOLOGIA Año: 2020 Tipo del documento: Article País de afiliación: Suecia Pais de publicación: Estados Unidos