Figure 1From: Swimming-induced exercise promotes hypertrophy and vascularization of fast skeletal muscle fibres and activation of myogenic and angiogenic transcriptional programs in adult zebrafishMorphometrical fibre parameters in fast muscle of exercised and non-exercised adult zebrafish. A: Image of the swim tunnels used for exercise training. Front tunnel: exercised zebrafish; back tunnel: non-exercised zebrafish. B-D: Images of zebrafish cross-sectional white muscle. Images correspond to representative serial transverse secions stained (B) for succinate dehydrogenase for the identification of fast, intermediate (pink) and slow muscle fibres; (C and D) for ATPase for capillary demonstration (arrows) and FCSA and FPER measures (white drawing) from a non-exercised (C) and an exercised (D) adult zebrafish. Bar represents 50 μm. Morphometric fibre parameters measured in non-exercised and exercised zebrafish were: FCSA, fibre cross-sectional area (μm2) (E); FPER, fibre perimeter (μm) (F); FD, fibre density (fibres/mm2) (G); SF, shape factor (H). Statistical significance values between non-exercised and exercised zebrafish: *P < 0.05. Values are mean ± SEM from a sample size of n = 8 for each condition. I-J: Fibre cross-sectional area histograms from fast muscle of exercised (I) and non-exercised (J) adult zebrafish. In K, the two overlapped curves are shown. Muscle fibre areas were grouped in intervals of 200 μm2 and the data correspond to mean ± SEM frequency of six animals. Curves represent a log-normal regression of four parameters. Regression parameters are shown in Additional file 1. See Methods for details.Back to article page