Decreased thin filament density and length in human atrophic soleus muscle fibers after spaceflight

• Published in: Journal of applied physiology (1985) 2000-02, Vol.88 (2), p.567-572
• Main Authors: Riley, Danny A, Bain, James L. W, Thompson, Joyce L, Fitts, Robert H, Widrick, Jeffrey J, Trappe, Scott W, Trappe, Todd A, Costill, David L
• Format: Article
• Language: English
• Subjects: Actin Cytoskeleton - metabolism; Applied physiology; Astronauts; Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Human physiology applied to population studies and life conditions. Human ecophysiology; Humans; Male; Medical sciences; Microscopy, Electron; Muscle Fibers, Skeletal - chemistry; Muscle Fibers, Skeletal - metabolism; Muscle, Skeletal - chemistry; Muscle, Skeletal - metabolism; Muscular Atrophy - physiopathology; Muscular system; Myofibrils - metabolism; Myofibrils - ultrastructure; Sarcomeres - metabolism; Sarcomeres - ultrastructure; Space biology; Space Flight; Space life sciences; Striated muscle. Tendons; Transports. Aerospace. Diving. Altitude; Vertebrates: osteoarticular system, musculoskeletal system; Weightlessness
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/jappl.2000.88.2.567

1  Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee 53226; 2  Department of Biology, Marquette University, Milwaukee, Wisconsin 53201; and 3  Human Performance Laboratory, Ball State University, Muncie, Indiana 47306 Soleus muscle fibers were examined electron microscopically from pre- and postflight biopsies of four astronauts orbited for 17 days during the Life and Microgravity Sciences Spacelab Mission (June 1996). Myofilament density and spacing were normalized to a 2.4-µm sarcomere length. Thick filament density (~1,062 filaments/µm 2 ) and spacing (~32.5 nm) were unchanged by spaceflight. Preflight thin filament density (2,976/µm 2 ) decreased significantly ( P