title: Cardiac morphology after conditions of microgravity during COSMOS 2044.
abstract: Light- and electron-microscopic studies were performed on cardiac muscle from rats flown on COS-MOS 2044 and from four control groups. Average cross-sectional area of myofibers was measured by video analysis of the light-microscopic images of papillary and ventricular muscle samples from all animals. This cross-sectional area was significantly decreased in flight rats (P = 0.03) compared with synchronous controls. Additional findings at the electron-microscopic level consistent with this atrophy were obtained by stereological analysis and optical diffraction analysis of papillary muscle samples. Slightly higher mitochondrial volume density values and mitochondria-to-myofibril ratios as well as normal A-band spacings (d1,0) and Z-band spacings of myofibrils were observed in the tail-suspension and flight groups. General morphological features similar to those in ventricular samples from the previous COSMOS 1887 flight were observed.
authors.affiliation: Department of Medicine, Baylor College of Medicine, Houston, Texas 77030.
authors.forename: M A
authors.initials: MA
authors.lastname: Goldstein
authors.forename: R J
authors.initials: RJ
authors.lastname: Edwards
authors.forename: J P
authors.initials: JP
authors.lastname: Schroeter
mesh_terms: D000818:Animals; D006321:Heart / Q000033:anatomy & histology / Q000502:physiology*; D008297:Male; D008854:Microscopy, Electron; D008870:Microtubules / Q000378:metabolism; D008929:Mitochondria, Heart / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism / Q000648:ultrastructure; D009210:Myofibrils / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D013026:Space Flight; D014893:Weightlessness / Q000009:adverse effects*