European Journal of Applied Physiology

, Volume 112, Issue 1, pp 155–162

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

  • Felicitas A. M. Huber-Abel
  • Mélanie Gerber
  • Hans Hoppeler
  • Oliver Baum
Original Article

DOI: 10.1007/s00421-011-1960-x

Cite this article as:
Huber-Abel, F.A.M., Gerber, M., Hoppeler, H. et al. Eur J Appl Physiol (2012) 112: 155. doi:10.1007/s00421-011-1960-x

Abstract

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 6 months, 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.

Keywords

AngiogenesisHuman exercise physiologyNeuronal nitric oxide synthaseSkeletal muscle

Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • Felicitas A. M. Huber-Abel
    • 1
  • Mélanie Gerber
    • 1
  • Hans Hoppeler
    • 1
  • Oliver Baum
    • 1
  1. 1.Institute of Anatomy, University of BernBernSwitzerland