Fig. 5.

Similar myoblast differentiation efficacy and myotube growth in 5 and 20% oxygen culture conditions. For all graphs, 5% oxygen culture conditions are represented by black bars and 20% oxygen culture conditions are represented by white bars. a Compared to the 6 h time point MyoD gene expression tended to increase three to six-fold between 24 h and 6 days post-differentiation. b–d In differentiating myotubes, myogenin, creatine kinase, and MyHC IIa mRNA levels were significantly increased at 6 days post-differentiation in both the 5 and 20% oxygen culture conditions (p < 0.05; main effect time). e Representative light microscopy image of multi-nucleated myotubes at 6 post-differentiation cultured in 5 or 20% oxygen and stained with an antibody reactive against all adult myosin heavy chain isoforms. Myosin heavy chain protein stained red; black scale bar represents 100 μm. f As a marker of hypertrophy, the total protein content of 0.25% SDS-solubilized 6 days old myotubes was determined and it was not different in the 5 and 20% oxygen culture conditions. (please refer to online manuscript for colour images)