The Role of Alveolar Macrophages in the Pathogenesis of Recurrent Airway Obstruction in Horses
Article first published online: 28 JUN 2008
© 2006 American College of Veterinary Internal Medicine
Journal of Veterinary Internal Medicine
Volume 20, Issue 1, pages 167–174, January 2006
How to Cite
Laan, T. T.J.M., Bull, S., Pirie, R. and Fink-Gremmels, J. (2006), The Role of Alveolar Macrophages in the Pathogenesis of Recurrent Airway Obstruction in Horses. Journal of Veterinary Internal Medicine, 20: 167–174. doi: 10.1111/j.1939-1676.2006.tb02837.x
- Issue published online: 28 JUN 2008
- Article first published online: 28 JUN 2008
- Revised March 22, 2005; Accepted July 22, 2005.
- Aspergillus fumigatus;
- ytokine expression;
- Hay dust solution;
When challenged with allergens and pro-inflammatory agents, such as Aspergillus fumigatus (AF), hay dust solution (HDS) and lipopolysaccharide (LPS), the innate immune response will not only activate the immune system but also increase the amount of pro-inflammatory cytokines in the bronchoalveolar space. The aim of this study was to assess the response of equine alveolar macrophages to different aerosolized challenges and to investigate the differences in this response between horses susceptible or nonsusceptible to recurrent airway obstruction (RAO). Seven susceptible and 5 nonsusceptible horses were challenged with saline, LPS, HDS, or AF, and bronchoalveolar lavage (BAL) cytology, total cell counts, and lung function were assessed. In addition, alveolar macrophages were isolated 6 and 24 hours after challenge, and macrophage mRNA expression of tumor necrosis factor (TNF)-α and interleukins (IL) IL-1β, IL-6, IL-8, and IL-10 were measured by means of real-time (RT) polymerase chain reaction (PCR). There was a significant difference in lung function, neutrophil ratios, and total cell counts in the bronchoalveolar lavage fluid between RAO-susceptible and nonsusceptible horses. In addition, the expression of TNF-α, IL-1β, and IL-8 by alveolar macrophages after challenges were higher in susceptible horses, than in nonsusceptible horses. In contrast, Il-6, considered an anti-inflammatory cytokine, showed a higher expression in nonsusceptible horses 6 hours after inhalation challenge with allergens and pro-inflammatory antigens. These data suggest that the differences between susceptible and nonsusceptible horses to RAO are not only dependent on adaptive immunity but also start with an innate immune response.