Effects of ozone exposure in rat lungs investigated with hyperpolarized 3He MRI

✍ Scribed by Yannick Crémillieux; Stéphane Servais; Yves Berthezène; David Dupuich; Aurélien Boussouar; Vasile Stupar; Jean-Marc Pequignot

• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: English
• Weight: 468 KB
• Volume: 27
• Category: Article
• ISSN: 1053-1807
• DOI: 10.1002/jmri.21216

✦ Synopsis

Abstract

Purpose

To investigate the effects of subchronic ozone exposure on rat lung ventilation using hyperpolarized (HP) ^3^He MRI.

Materials and Methods

A total of 24 Sprague‐Dawley rats, distributed in one control group and four groups exposed to 0.5 ppm ozone concentration for two days or six days, either continuously (22 hours/day) or alternatingly (12 hours/day). A three‐step MRI protocol was designed and applied to each animal, including: 1) ^3^He gas distribution images acquired at inspiratory capacity, 2) measurements of intrapulmonary ^3^He diffusion coefficients, and 3) dynamic ventilation acquisitions performed during lung filling with ^3^He.

Results

No differentiation between animals exposed to ozone and control animals was observed from the ventilation images obtained at inspiratory capacity. The ^3^He diffusion coefficients were not statistically different from one group to another. Ventilation defects, appearing as delayed lung filling regions and heterogeneous lung filling, were observed in the dynamic lung ventilation image series. The percentage of animals with ventilation defects in the control, two‐day, and six‐day exposed groups were equal to 20%, 43% and 75%, respectively. In the subgroup of the animals exposed six days for 12 hours per day, the percentage of animals exhibiting ventilation defects was equal to 85%.

Conclusion

Heterogeneous obstructive patterns in an experimental animal model of subchronic ozone exposure were observed using HP ^3^He MRI. J. Magn. Reson. Imaging 2008;27:771–776. © 2008 Wiley‐Liss, Inc.