Skeletal muscle satellite cells (SC) are of key importance for muscle fiber regeneration, repair and remodeling. A prolonged period of bed rest results in a substantial loss of muscle mass, which is accompanied by a reduction in SC content. In resting skeletal muscle tissue, blood flow restriction (BFR) has been reported to stimulate myogenesis and muscle fiber hypertrophy in animals. However, whether BFR treatment can attenuate the decline in muscle fiber size and SC number during a period of bed rest in humans remains unknown.

Twelve healthy, non-obese men (age: 24±4 y; BMI: 23.7±3.1 kg/m²) were subjected to 2 weeks of bed rest, during which one leg was exposed to 3 times daily BFR, whereas the contralateral leg received sham treatment (CON). Before and immediately after the 2 weeks of bed rest, leg lean tissue mass was assessed by DXA-scan. Muscle biopsies were obtained from the vastus lateralis before and after the 2 weeks of bed rest from both legs. Type I and type II muscle fiber size, myonuclear and SC content were assessed by immunohistochemistry.

Leg lean mass decreased in response to 2 weeks of bed rest (P<0.05), with no differences between the BFR and CON leg (P=0.62). Type I and type II muscle fiber size tended (P=0.06) to decline following bed rest in the CON leg only. Myonuclear content remained unchanged in either leg. Type I and type II muscle SC content expressed per 100 fibers declined over time, with no differences between legs (main effect of time, P<0.05). SC density, expressed per millimeter squared, tended (main effect of time, P=0.07) to decline in response to bed rest in either leg.

Daily blood flow restriction treatment does not attenuate the decline in leg lean mass or SC content during two weeks of bed rest in healthy, young men.