Retinoic acid induces nonuniform alveolar septal growth after right pneumonectomy

Xiao Yan, Dennis J. Bellotto, David J. Foster, Robert L. Johnson, Herbert K. Hagler, Aaron S. Estrera, Connie C W Hsia

Research output: Contribution to journalArticlepeer-review

33 Scopus citations

Abstract

To determine whether all-trans retinoic acid (RA) enhances compensatory lung growth in fully mature animals, adult male dogs (n = 4) received 2 mg·kg-1·day-1 po RA 4 days/wk beginning the day after right pneumonectomy (R-PNX, 55-58% resection). Litter-matched male R-PNX controls (n = 4) received placebo. After 4 mo, the remaining lung was fixed by tracheal instillation of fixatives at a constant airway pressure for detailed morphometric analysis. After RA treatment compared with placebo, lung volume was slightly but not significantly lower. Volume density of septum to lung was 37% higher because of a 50 and 25% higher volume density of capillary and septal tissue, respectively. Mean septal thickness was 27% higher. Absolute volumes of endothelial cells and capillary blood were 31-37% higher, whereas epithelial and interstitial volumes were not different between groups. Absolute alveolar-capillary surface areas did not differ between groups, and alveolar septal surface-to-volume ratio was 20% lower in RA-treated animals. RA treatment exaggerated interlobar differences in morphometric indexes and caused alveolar capillary morphology to revert to a more immature state. Thus RA treatment during early post-R-PNX adaptation preferentially enhanced alveolar capillary and endothelial cell volumes consistent with formation of new capillaries, but the associated septal distortion precluded a corresponding increase in gas-exchange surface or morphometric estimates of lung diffusing capacity.

Original languageEnglish (US)
Pages (from-to)1080-1089
Number of pages10
JournalJournal of applied physiology
Volume96
Issue number3
DOIs
StatePublished - Mar 2004

Keywords

  • Alveolar capillary growth
  • Compensatory lung growth
  • Dog
  • Endothelial cell volume
  • Lung morphometry

ASJC Scopus subject areas

  • General Medicine

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