Hyperoxia-induced pulmonary vascular and lung abnormalities in young rats and potential for recovery

ABSTRACT ABSTRACT.: We carried out morphometric studies to assess the effects of increasing durations of hyperoxic exposure on the developing rat lung and to evaluate the potential for new

growth and for regression of structural abnormalities on return to room air. From day 10 of life Sprague-Dawley rats were either exposed to hyperoxia (O.8FIO2) for 2-8 wk or were removed

after 2 wk and allowed to “recover” in room air for 2-6 wk. Litter mates maintained in room air served as age matched controls. Every 2 wk experimental and control rats from each group were

weighed and killed. The heart and lungs were removed, the pulmonary artery was injected with bariumgelatin, and the lung was fixed in formalin in the inflated state. Morphometric assessments

were made of right and left ventricular weights, lung volume, axial artery lumen diameter, alveolar number and concentration, and arterial number, concentration and muscularity. Rats

continuously exposed to hyperoxia and rats exposed for only 2 wk showed the same degree of impaired parenchymal lung growth, as judged by a decrease in the concentration and number of

alveoli. A significant decrease in arterial concentration, increase in muscularization of peripheral arteries, and medial hypertrophy of muscular arteries occurred after 2 wk of hyperoxia.

Despite an initial trend toward regression, these features became progressively severe with continued hyperoxic exposure and by 8 wk were associated with a decreased arterial lumen diameter,

with right ventricular hypertrophy and with failure to thrive. In rats exposed to hyperoxia for 2 wk and then returned to room air there was a persistent decrease in arterial number and an

increase in muscularization but both features were less severe than in rats continuously exposed. Thus, an 8-wk exposure to hyperoxia in rats from day 10 of life results in decreased lung

and vascular growth and in increased muscularity. Even a relatively short 2-wk exposure is associated with impaired alveolar growth and vascular abnormalities which persist into “adult”

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SIMPLIFICATION IN MICE Article 03 November 2020 ARTICLE PDF AUTHOR INFORMATION AUTHORS AND AFFILIATIONS * Departments of Cardiology and Pathology, The Hospital for Sick Children and

Departments of Pediatrics and Pathology, Research Institute, University of Toronto, Toronto, Canada Wendy Lee Wilson, Michelle Mullen, Peter M Olley & Marlene Rabinovitch Authors * Wendy

Lee Wilson View author publications You can also search for this author inPubMed Google Scholar * Michelle Mullen View author publications You can also search for this author inPubMed 

Google Scholar * Peter M Olley View author publications You can also search for this author inPubMed Google Scholar * Marlene Rabinovitch View author publications You can also search for

this author inPubMed Google Scholar RIGHTS AND PERMISSIONS Reprints and permissions ABOUT THIS ARTICLE CITE THIS ARTICLE Wilson, W., Mullen, M., Olley, P. _et al._ Hyperoxia-Induced

Pulmonary Vascular and Lung Abnormalities in Young Rats and Potential for Recovery. _Pediatr Res_ 19, 1059–1067 (1985). https://doi.org/10.1203/00006450-198510000-00023 Download citation *

Received: 15 January 1985 * Accepted: 04 June 1985 * Issue Date: 01 October 1985 * DOI: https://doi.org/10.1203/00006450-198510000-00023 SHARE THIS ARTICLE Anyone you share the following

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