Original Paper

Histochemistry and Cell Biology

, Volume 129, Issue 1, pp 65-72

First online:

Network distribution of mitochondria and lipid droplets in human muscle fibres

  • Christopher S. ShawAffiliated withExercise Metabolism Research Group, School of Sport and Exercise Sciences, The University of Birmingham
  • , David A. JonesAffiliated withExercise Metabolism Research Group, School of Sport and Exercise Sciences, The University of Birmingham
  • , Anton J. M. WagenmakersAffiliated withExercise Metabolism Research Group, School of Sport and Exercise Sciences, The University of Birmingham Email author 

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Abstract

The objective of the present study was to develop a combination of fluorescent stains that would allow visualisation of the network of mitochondria and lipid droplets (intramyocellular lipids or IMCL) in human skeletal muscle fibres by means of conventional and confocal microscopy. Muscle biopsies were taken from the vastus lateralis of three lean, healthy and physically active male subjects. Frozen muscle sections were stained for mitochondria using antibodies against three mitochondrial proteins; porin, cytochrome c oxidase (COX) and NADH-ubiquinol oxidoreductase and neutral lipids were stained with oil red O. Anti-COX staining produced images with the strongest fluorescence signal and the highest resolution of the mitochondrial network and this stain was successfully combined with the antibody against type I fibre myosin. A highly organised matrix arrangement of mitochondria within the sarcomeres (in pairs at the I-band) was observed in the oxidative type I fibres. The density of mitochondria was the highest in the subsarcolemmal region. Anti-COX staining was combined with oil red O demonstrating that in type I fibres lipid droplets are mainly located in the space between the mitochondria.

Keywords

Mitochondria Intramyocellular lipids Fluorescence Confocal imaging Skeletal muscle