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Exercise-induced angiogenesis correlates with the up-regulated expression of neuronal nitric oxide synthase (nNOS) in human skeletal muscle

Huber-Abel, Felicitas ; Gerber, Mélanie ; Hoppeler, Hans ; Baum, Oliver

In: European Journal of Applied Physiology, 2012, vol. 112, no. 1, p. 155-162

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    Titre
    • Exercise-induced angiogenesis correlates with the up-regulated expression of neuronal nitric oxide synthase (nNOS) in human skeletal muscle
    Auteur
    • Huber-Abel, Felicitas. Institute of Anatomy, University of Bern, Baltzerstrasse 2, 3009, Bern, Switzerland
    • Gerber, Mélanie. Institute of Anatomy, University of Bern, Baltzerstrasse 2, 3009, Bern, Switzerland
    • Hoppeler, Hans. Institute of Anatomy, University of Bern, Baltzerstrasse 2, 3009, Bern, Switzerland
    • Baum, Oliver. Institute of Anatomy, University of Bern, Baltzerstrasse 2, 3009, Bern, Switzerland
    Type de document
    • Postprint
    Langue
    • Anglais
    Publié dans
    • European Journal of Applied Physiology, 2012, vol. 112, no. 1, p. 155-162. Springer-Verlag
    Autre version électronique
    Identifiant OAI-PMH
    • oai:doc.rero.ch:320378
    Summary
    The contribution of neuronal nitric oxide synthase (nNOS) to angiogenesis in human skeletal muscle after endurance exercise is controversially discussed. We therefore ascertained whether the expression of nNOS is associated with the capillary density in biopsies of the vastus lateralis (VL) muscle that had been derived from 10 sedentary male subjects before and after moderate training (four 30-min weekly jogging sessions for 6months, with a heart-rate corresponding to 75% VO2max). In these biopsies, nNOS was predominantly expressed as alpha-isoform with exon-mu and to a lesser extent without exon-mu, as determined by RT-PCR. The mRNA levels of nNOS were quantified by real-time PCR and related to the capillary-to-fibre ratio and the numerical density of capillaries specified by light microscopy. If the VL biopsies of all subjects were co-analysed, mRNA levels of nNOS were non-significantly elevated after training (+34%; P>0.05). However, only five of the ten subjects exhibited significant (P≤0.05) elevations in the capillary-to-fibre ratio (+25%) and the numerical density of capillaries (+21%) and were thus undergoing angiogenesis. If the VL biopsies of these five subjects alone were evaluated, the mRNA levels of nNOS were significantly up-regulated (+128%; P≤0.05) and correlated positively (r=0.8; P≤0.01) to angiogenesis. Accordingly, nNOS protein expression in VL biopsies quantified by immunoblotting was significantly increased (+82%; P≤0.05) only in those subjects that underwent angiogenesis. In conclusion, the expression of nNOS at mRNA and protein levels was statistically linked to capillarity after exercise suggesting that nNOS is involved in the angiogenic response to training in human skeletal muscle