Recovery of airway structure and function after hyperoxic exposure in immature rats
| Autor: | Edward T. Naureckas, Marc B. Hershenson, Allan Garland, Julian Solway, Anne Zimmermann, Valeria J. Rubinstein, Michael D. Kelleher, Mark K. Abe |
|---|---|
| Rok vydání: | 1994 |
| Předmět: |
Pulmonary and Respiratory Medicine
medicine.medical_specialty Pathology Time Factors Biopsy Bronchi Critical Care and Intensive Care Medicine Bronchial Provocation Tests Epithelium Muscle hypertrophy Rats Sprague-Dawley Airway resistance Internal medicine Administration Inhalation Image Processing Computer-Assisted medicine Animals Humans Aerosols Hyperoxia Analysis of Variance Bronchus Lung Dose-Response Relationship Drug business.industry Airway Resistance Body Weight Smooth muscle layer Age Factors Muscle Smooth Hypertrophy respiratory system Acetylcholine Rats Oxygen Dose–response relationship medicine.anatomical_structure Endocrinology Linear Models Bronchial Hyperreactivity medicine.symptom business Airway |
| Zdroj: | American Journal of Respiratory and Critical Care Medicine. 149:1663-1669 |
| ISSN: | 1535-4970 1073-449X |
| DOI: | 10.1164/ajrccm.149.6.8004327 |
| Popis: | We have previously demonstrated that hyperoxic exposure (> 95% O2 for 8 d) induces airway cholinergic hyperresponsiveness and remodeling in 21-d-old rats. To examine the potential relationship between airway hyperresponsiveness and remodeling in these animals, we exposed rats to air or hyperoxia for 8 d, returned them to air-breathing, and measured airway responsiveness to inhaled acetylcholine (ACh) and layer thicknesses immediately after or 16 or 48 d after cessation of air or O2 exposure. The ACh concentration required to increase resistance by 100% (EC200ACh) was calculated by linear interpolation. Small airway (circumference < 1,000 microns) and medium-sized, conducting airway (1,000 to 3,000 microns) epithelial and smooth muscle layer mean thicknesses and fractional areas (layer area/luminal cross-sectional area) were determined from lung sections by contour tracing using a digitizing pad and computer. As we reported previously, after 8 d of O2 exposure, group mean log EC200ACh was significantly reduced relative to that in control animals (p < 0.001). Similarly, hyperoxic exposure was associated with significant increases in all parameters of airway layer thickness assessed (p < 0.05). However, by 16 d after cessation of O2 exposure, there were no longer statistically significant differences in log EC200ACh, airway layer thickness, or fractional area between control and O2-exposed animals. Further studies, in a second cohort of animals killed 0, 3, 6, 8, or 13 d after cessation of O2 exposure, demonstrated progressive reductions in small airway epithelial and smooth muscle layer thicknesses, confirming that hyperoxia-induced airway remodeling resolves by approximately 2 wk after termination of O2 exposure.(ABSTRACT TRUNCATED AT 250 WORDS) |
| Databáze: | OpenAIRE |
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