title: Growth characteristics of Juxta-alveolar smooth muscle cells derived from high-altitude-hypoxia sheeplung parenchyma.
abstract: OBJECTIVE
  Pathologic effects of environmental factors on smooth muscle cells (SMCs) near the air/blood interface have been difficult to study because it is impossible to dissect blood vessels and bronchi down to their alveolar terminals. SMCs derived from explants of lung terminal parenchyma were examined in order to detect any effect of chronic hypoxia on their growth profiles.
  
  
  METHODS
  Lungs were obtained from sheep kept at 12, 470 ft altitude, PaO2  ~60 Torr for ~4 months and from age matched control sheep kept at sea level.  SMC were allowed to migrate from terminal lung parenchyma. Monolayer growth profiles were studied by using tritiated thymidine incorporation as indicator of DNA synthesis.
  
  
  RESULTS
  The normal growth pattern, typified by intrapulmonary 7th  generation vein SMCs, showed a peak at 72h and mean peak tritiated thymidine incorporation (counts per minute, cpm) of 2829.46±294.24.  Fifteen SMC lines were obtained from hypoxic sheep lungs compared to control sheep which generated three lines. According to peaks and mean incorporated cpm, hypoxic cells showed five distinct growth profiles: normal, subprolific, prolific, retarded, and senescent.   Mean peak cpm incorporated by subprolific and prolific cells were: 4480.80±240.22 and 7775.42±475.77 cpm. The normal cells incorporated 507.04, 1386.33, 936.08, and -944.29 cpm in the 1st, 2nd, 3rd   and 4th  24h-periods respectively while the retarded cells incorporated 403.70, 491.7, 53.08, and -124.08 cpm, and the senescent cells incorporated 26.71, 7.04, 7.83, and -0.42 cpm respectively. Apoptotic cells were also derived from hypoxic tissues.
  
  
  CONCLUSIONS
  This report indicates an origin of pulmonary pathology, the SMC's near the air/blood interface.
authors: Department of Pharmacology, Lagos State University College of Medicine.
authors: A J
authors: AJ
authors: Theresa
mesh_terms: D056151:Airway Remodeling; D000531:Altitude; D000532:Altitude Sickness / Q000473:pathology*; D000818:Animals; D049109:Cell Proliferation; D016922:Cellular Senescence; D000860:Hypoxia / Q000150:complications / Q000378:metabolism; D008168:Lung / Q000378:metabolism / Q000473:pathology; D008954:Models, Biological; D032389:Myocytes, Smooth Muscle / Q000378:metabolism / Q000473:pathology; D010100:Oxygen / Q000378:metabolism; D012756:Sheep; D013936:Thymidine / Q000494:pharmacology
chemical_list: D010100:Oxygen; D013936:Thymidine