title: Morphologic multiplicity of smooth muscle cell monolayers from extreme lung parenchyma of high-altitude-hypoxia sheep.
abstract: BACKGROUND
  Chronic hypoxia causes lung pathology but little is known about how morphologic changes occur or about the progenitor cells of lung remodeling. Since the alveolar region is the first site of environmental challenge, smooth muscle cell (SMC) monolayers derived from close to the alveoli were studied for morphologic patterns. Thus we aimed to deduce any impact of environmental challenge on juxta-alveolar cells and identify phenotypical changes that are suspect precedence to lung pathologies such as cancer. METHODS.: Lung tissues from freshly sacrificed adult sheep that had been kept in high altitude hypoxia for approximately 4 months were used. The lung tissues were studied for macroscopic signs of pathology. Lung parenchymal explants from approximately 0.5-1.5 mm to the lung edge were cultured for isolation of upper generation SMCs which are closer to the air/blood interphase. The cells were characterized by fluorescence immunohistochemistry using a monoclonal antibody against alpha-smooth muscle actin. The monolayer morphologies of the derived stable cell lines were compared.
  
  
  RESULTS
  We observed that the distal lung parenchyma of the chronically hypoxic sheep yielded six distinct smooth muscle cell morphological varieties: apoptotic, sub-confluent, spindle-form, hill and valley, swirl, and rhomboid monolayers. The control sheep lungs yielded two varieties of smooth muscle cells: swirl and hill-and-valley monolayer formations at confluence. All the cell lines were jointly generated from the terminals of the vascular and bronchiolar trees.
  
  
  CONCLUSIONS
  Chronic high altitude hypoxia appears to induce morphological variation in juxta-alveolar smooth muscle cells in the ovine lung.
authors: Department of Pharmacology, Lagos State University College of Medicine, 1 Oba Akinjobi Way, GRA, Ikeja, Lagos, Nigeria. theresaadebola@yahoo.com
authors: T A
authors: TA
authors: John
mesh_terms: D000531:Altitude; D000818:Animals; D005260:Female; D000860:Hypoxia; D008168:Lung / Q000166:cytology* / Q000378:metabolism / Q000473:pathology; D009130:Muscle, Smooth / Q000378:metabolism / Q000473:pathology*; D012756:Sheep