Journal of Applied Physiology, Vol 78, Issue 1 124-131, Copyright © 1995 by American Physiological Society

ARTICLES

Lung growth in hypobaric normoxia, normobaric hypoxia, and hypobaric hypoxia in growing rats. I. Biochemistry

H. S. Sekhon and W. M. Thurlbeck
Department of Pathology, University of British Columbia, Faculty of Medicine, Vancouver, Canada.

Adaptive changes in cellular and connective tissue components of the lung after chronic exposure to reduced ambient oxygen and/or pressure were studied. Four-week-old male Sprague-Dawley rats were randomly divided into five groups (n = 12 each): 1) general control, room air (GC); 2) hypobaric normoxic; 3) normobaric hypoxic; 4) hypobaric hypoxic; and 5) weight-matched control, restricted food intake (WMC; weight matched to hypobaric hypoxic animals). Lung growth (lung weight and DNA, RNA, protein, hydroxyproline, and desmosine contents) diminished in WMC compared with GC. Somatic growth decreased in hypobaric and normobaric hypoxic rats compared with GC. Lung weight; DNA, RNA, protein, hydroxyproline, and desmosine contents; and RNA/DNA, protein/DNA, and desmosine/DNA ratios increased in both hypobaric and normobaric hypoxic rats compared with WMC. Hydroxyproline and desmosine contents and the hydroxyproline/DNA ratio were significantly higher in hypobaric than normobaric hypoxic rats. Hypobaric normoxia caused a slight somatic growth reduction, but biochemical parameters of lung growth remained unaffected. In conclusion, in growing animals, despite inhibition of lung growth due to reduced food consumption, accelerated lung growth in hypobaric or normobaric hypoxia occurs by hyperplastic and hypertrophic changes. Hypobaric normoxia does not affect lung growth, but connective tissue proteins accumulate slightly more in hypobaric hypoxia than in hypoxia alone.

This article has been cited by other articles:

				T. Owerkowicz, R. M. Elsey, and J. W. Hicks Atmospheric oxygen level affects growth trajectory, cardiopulmonary allometry and metabolic rate in the American alligator (Alligator mississippiensis) J. Exp. Biol., May 1, 2009; 212(9): 1237 - 1247. [Abstract] [Full Text] [PDF]

				C. C. W. Hsia, R. L. Johnson Jr, P. McDonough, D. M. Dane, M. D. Hurst, J. L. Fehmel, H. E. Wagner, and P. D. Wagner Residence at 3,800-m altitude for 5 mo in growing dogs enhances lung diffusing capacity for oxygen that persists at least 2.5 years J Appl Physiol, April 1, 2007; 102(4): 1448 - 1455. [Abstract] [Full Text] [PDF]

				P. McDonough, D. M. Dane, C. C. W. Hsia, C. Yilmaz, and R. L. Johnson Jr. Long-term enhancement of pulmonary gas exchange after high-altitude residence during maturation J Appl Physiol, February 1, 2006; 100(2): 474 - 481. [Abstract] [Full Text] [PDF]

				Mechanisms and Limits of Induced Postnatal Lung Growth Am. J. Respir. Crit. Care Med., August 1, 2004; 170(3): 319 - 343. [Full Text] [PDF]

				A. F. Corno, G. Milano, M. Samaja, P. Tozzi, and L. K. von Segesser Chronic hypoxia: A model for cyanotic congenital heart defects J. Thorac. Cardiovasc. Surg., July 1, 2002; 124(1): 105 - 112. [Abstract] [Full Text] [PDF]