Am. J. Respir. Crit. Care Med.,
Volume 157, Number 5, May 1998, 1512-1521
Effect of Route of Breathing on Response to Exposure in
a Swine Confinement Building
YVON
CORMIER,
MICHEL
LAVIOLETTE,
GAETANE
BEDARD,
JAMES
DOSMAN,
and
EVELYNE
ISRAEL-ASSAYAG
Unité de Recherche, Centre de Pneumologie, Hôpital and Université Laval, Ste-Foy, Quebec; and Centre for Agricultural Medicine,
University of Saskatchewan, Saskatoon, Saskatchewan, Canada
Exposure of naive subjects to swine buildings results in acute nasal, lung, and peripheral blood inflammatory responses with an increase in nonallergic airway responsiveness. Because nasal passages
filter large particles and soluble gases and because swine building exposure results in an acute inflammatory response at this level, we questioned what effect breathing through or avoiding this
route would have on local and systemic inflammation. Nine normal young men 23 to 37 yr of age
were exposed for 5 h to a swine building, once breathing normally and once with the mouth occluded (n = 8) (Protocol 1) or the nose occluded (n = 4) (Protocol 2); three subjects participated in
both protocols. For each protocol each subject underwent a methacholine challenge for PC20 measurement, a nasal lavage, venous blood puncture, and a bronchoalveolor lavage (BAL) once before
and once after each swine building exposure. Bronchial responsiveness as measured by PC20 decreased in most subjects after swine building exposure and was not influenced by the route of
breathing. Nasal lavage neutrophils increased tenfold after each swine exposure, except when the
nose was occluded where no alteration was observed. Total BAL cells significantly increased after
each exposure to the swine building, this increase was not modified by the route of breathing. In Protocol 1, white blood cells increased from a baseline level of 7.0 to 10.5 × 109 cells/L after exposure
with normal breathing and to 10.7 × 109 cells/L during nasal breathing exclusively. For Protocol 2, these respective values were: 5.6, 11.7 and 10.4 × 109/L. Interleukins 6 and 8 levels in BAL, nasal
washes, and serum were increased by swine building exposure, except in the nasal wash when the
nose was occluded. In conclusion, the lung and blood responses to exposure in a swine confinement
building are not modified by the route of breathing, suggesting that nasal inflammation and filtration are not important in the process and that small respirable particles and/or gases may be responsible for these responses.
