Cell cycle kinetics following an acute bout of resistance exercise.

<p>SC cell cycle kinetics in response to a bout of resistance exercise was analyzed through flow cytometry analysis of Pax7/PI staining in the acute time-course pre-training. Percentage of SC (Pax7⁺) in (A) all cell cycle phases (G_o/G_I, S, G₂/M), and (B) S-phase are demonstrated. Representative FACS plots of cell cycle of Pax7+ cells pre (C), 24 h (D) and 72 h (E) following an acute bout of exercise. S phase is highlighted in each representative plot. Pax7+ cells in S phase represent 8.2% (C), 9.2% (D), and 12.3% (E) of total cells pre, 24 h and 72 h respectively. * denotes a significant difference from respective Pre timepoint (p<0.01).</p

The association of MSTN with SC following an acute bout of resistance exercise and 16 wks of resistance training.

<p>(A), representative image (merge) of a MSTN/Pax7/Laminin/MHCI immunofluorescent stain. The arrow denotes a MSTN+/Pax7+ cell associated to a type 2 fibre. Single channel views of (a) Pax7 (red), (b) MSTN (yellow), (c) DAPI (blue), and (d) MHCI and Laminin (green) are provided, scale bar measures 10 µm. Quantification of MSTN colocalization to SCs was done in a fiber type specific manner. The changes in colocalization as a result of (B) an acute bout of resistance exercise and (C) 16 weeks of training is displayed. * and ** denote significant differences from the pre timepoint (p<0.05 and p<0.001 respectively). # and ## denote significant differences from the 24 hour timepoint (p<0.05 and p<0.001 respectively).</p

Myonuclear contribution to muscle hypertrophy.

<p>Myonuclear content and fibre size were quantified by visualization of nuclei (Pax7/DAPI) and myofibre borders (laminin) on muscle cross sections. Calculations of (A) myonuclear domain (fibre area (µm2) per nucleus) and (B) nuclei per muscle fibre cross section are reported. * denotes a significant difference from pre-training (p<0.05).</p

The SC response to an acute bout of resistance exercise and to 16 wks of resistance training.

<p>(A), representative image (merge) of a Pax7/Laminin/MHCI/MCHII immunofluorescent stain. Arrow denotes a Pax7+ cell associated with a type 2 fibre. Single channel views of (a) Pax7 (pink), (b) DAPI (blue), (c) MHCII (red), (d) MHCI and laminin (green)are provided. Scale bar measures 10 µm. SC response to (B) an acute bout of resistance exercise and (C) 16 weeks of training are expressed as satellite cell number per 100 myofibres and are specific to fiber type. Changes in SC number correspond to increases in whole muscle Pax7 mRNA in both (C) the acute time course and (D) the training response of Pax7 mRNA. * denotes significant differences from pre- time point (p≤0.05).</p