Regulation of Satellite Cells and Myogenesis in Response to Eccentric Resistance Exercise in Hypoxic Conditions in Healthy Young Men

Satellite cells participate in myogenesis and contribute to skeletal muscle regeneration and hypertrophy. Amongst other stimuli, satellite cells can be activated by exercise and hypoxia. However, the cumulative effect of exercise on hypoxia on myogenesis is not well understood, certainly in humans. Furthermore, whether satellite cell activation and myogenesis differ between environmental hypoxia and blood flow restriction is not known. The purpose of this study was to analyze satellite cell and myogenic markers in response to acute eccentric resistance exercise in normoxia, normobaric environmental hypoxia, and with blood flow restriction (local hypoxia). Thirty-eight healthy young men were allocated to one of the three experimental conditions: normoxia (n = 13), normobaric environmental hypoxia (n = 12), and blood flow restriction (n = 13). They all performed 5 series of 15 repetitions at 60°/s for the knee extension and 30°/s for the knee flexion on an isokinetic dynamometer. Vastus lateralis muscle biopsies and blood samples were taken before, 1, 24, and 72 h after exercise. Myogenic regulatory factor expression was upregulated after exercise similarly in the normoxic and hypoxic groups and attenuated in the blood flow restriction group. Despite differential regulation of myogenic regulatory factor expression and circulating creatine kinase levels after eccentric resistance exercise, none of the investigated hypoxia markers and immediate early genes, inflammatory markers, growth factors, except insulin-like growth factor-1, and mitogen-activated protein kinase members were differently regulated between the groups. Contrary to our hypothesis, satellite cell activation and myogenesis were not potentiated by the combination of eccentric resistance exercise and hypoxic conditions.