Cosmos 1887: morphology, histochemistry, and vasculature of the growing rat tibia

• Published in: The FASEB journal Vol. 4; no. 1; p. 16
• Main Authors: Doty, S B, Morey-Holton, E R, Durnova, G N, Kaplansky, A S
• Format: Journal Article
• Language: English
• Published: United States 01.01.1990
• Subjects: Alkaline Phosphatase - metabolism; Animals; Blood Vessels - anatomy & histology; Bone Development - physiology; Histocytochemistry; Male; Microscopy, Electron; Nucleotidases - metabolism; Osteoblasts - ultrastructure; Osteocytes - ultrastructure; Rats; Rats, Inbred Strains; Space Flight; Tibia - anatomy & histology; Tibia - blood supply; Tibia - physiology; Weightlessness; NASA Program Space Biology; NASA Center ARC; NASA Discipline Developmental Biology; NASA Experiment Number COS 1887-3; NASA Discipline Number 00-00; NASA Program Flight; NASA Discipline Number 26-20; Non-NASA Center
• ISSN: 0892-6638
• DOI: 10.1096/fasebj.4.1.2153083

Light microscopy, electron microscopy, and enzyme histochemistry were used to study the effects of spaceflight on metaphyseal and cortical bone of the rat tibia. Cortical cross-sectional area and perimeter were not altered by a 12.5-day spaceflight in 3-month-old male rats. The endosteal osteoblast population and the vasculature near the periosteal surface in flight rats compared with ground controls showed more pronounced changes in cortical bone than in metaphyseal bone. The osteoblasts demonstrated greater numbers of transitional Golgi vesicles, possibly caused by a decreased cellular metabolic energy source, but no difference in the large Golgi saccules or the cell membrane-associated alkaline phosphatase activity. The periosteal vasculature in the diaphysis of flight rats often showed lipid accumulations within the lumen of the vessels, occasional degeneration of the vascular wall, and degeneration of osteocytes adjacent to vessels containing intraluminal deposits. These changes were not found in the metaphyseal region of flight animals. The focal vascular changes may be due to ischemia of bone or a developing fragility of the vessel walls as a result of spaceflight.