Hyperoxia-induced airway remodeling in immature rats: Correlation with airway responsiveness

M. B. Hershenson*, A. Garland, M. D. Kelleher, A. Zimmermann, C. Hernandez, J. Solway

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

27 Scopus citations

Abstract

We recently found that exposure of 21-day-old rats to hyperoxia (>95% O2 for 8 days) significantly increased in vivo airway cholinergic responsiveness and that O2 exposure also increased airway epithelial and smooth muscle layer thicknesses in a separate cohort of animals. There was substantial variation in the magnitude of both the functional and structural responses to hyperoxia. The present study was designed to test whether the magnitude of O2-induced airway remodeling could account for individual differences in airway responsiveness after O2 exposure, as well as for the difference in responsiveness between air- and O2-exposed animals. We assessed in vivo airway responsiveness to aerosolized acetylcholine (ACh) and airway architecture in 14 O2- and 5 air-exposed, immature rats. Total respiratory system resistance was determined using a plethysmographic method. The mean thicknesses and fractional areas of the airway epithelial and smooth muscle layers were determined by contour tracing using a digitizing pad and microcomputer. Both the small (circumference < 1,000 μm) and central (circumference 1,000 to 4,000 μm) airways were studied. For O2-exposed rats, individual values of EC200 ACh correlated negatively with small airway smooth muscle layer thickness (r = -0.59, p < 0.05; ANOVA), small airway smooth muscle layer fractional area (r = -0.75, p < 0.01), small airway epithelial thickness (r = -0.54, p < 0.05), small airway epithelial fractional area (r = -0.69, p < 0.01), and central airway smooth muscle layer thickness (r = -0.53, p < 0.05). When both air- and O2-exposed animals were considered, EC200 ACh correlated negatively with all eight parameters of airway layer thickness and fractional area. These correlations are consistent with the notion that, in immature rats, airway wall layer thickness in part determines airway responsiveness.

Original languageEnglish (US)
Pages (from-to)1294-1300
Number of pages7
JournalAmerican Review of Respiratory Disease
Volume146
Issue number5
DOIs
StatePublished - 1992

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine

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