Early onset airway obstruction in response to organic dust in the horse
José Cunilleras, Eduard (Universitat Autònoma de Barcelona. Departament de Medicina i Cirurgia Animals)
Marlin, David J. (Animal Health Trust. Department of Physiology)
Deaton, Christopher M. (Animal Health Trust. Department of Physiology)
Vincent, Thea L. (Hartpury College)
Baird, Alan W. (University College Dublin. School of Agriculture, Food Science and Veterinary Medicine)
Dacre, K. (Royal (Dick) School of Veterinary Studies. Department of Veterinary Clinical Sciences)
Deaton, Laura (Animal Health Trust. Department of Physiology)

Date:	2007
Abstract:	Equine recurrent airway obstruction (RAO) has been used as a naturally occurring model of human asthma. However, it is unknown whether there is an early-phase response in RAO. The aim of this study was to determine whether exposure to organic dust induces immediate changes in lung function in RAO-affected horses, which could be mediated by airway mast cells. Six RAO-affected horses in remission and six control horses were challenged with hay-straw dust suspension by nebulization. Total respiratory resistance at 1 Hz, measured by forced oscillation, was increased from 0. 62 +/- 0. 09 cmH(2)O. l(-1). s (mean +/- SE) to 1. 23 +/- 0. 20 cmH(2)O. l(-1). s 15 min after nebulization in control horses (P = 0. 023) but did not change significantly in the RAO group. Total respiratory reactance at 1 Hz (P = 0. 005) was significantly lower in the control horses (-0. 77 +/- 0. 07 cmH(2)O. l(-1). s) than in the RAO group (-0. 49 +/- 0. 04 cmH(2)O. l(-1). s) 15 min after nebulization. Bronchoalveolar lavage fluid (BALF) histamine concentration was significantly elevated 10 and 20 min postnebulization in control horses but not in RAO horses. Minimum reactance at 1 Hz in the early postnebulization period significantly correlated with both prechallenge BALF mast cell numbers (r = -0. 65, P = 0. 02) and peak BALF histamine concentration postnebulization (r = -0. 61, P = 0. 04). In conclusion, RAO horses, unlike human asthmatic patients, do not exhibit an early-phase response. However, healthy control horses do demonstrate a mild but significant early (<20 min) phase response to inhaled organic dust. This response may serve to decrease the subsequent dose of dust inhaled and as such provide a protective mechanism, which may be compromised in RAO horses.
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Cavalls ; Pneumologia veterinària ; Aparell respiratori ; Malalties ; Equine ; Lung function ; Allergen
Published in:	Journal of Applied Physiology, Vol. 102 (2007) , p. 1071-1077

DOI: 10.1152/japplphysiol.00264.2006
PMID: 17158251

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