Am. J. Respir. Crit. Care Med.,
Volume 157, Number 5, May 1998, 1531-1535
Tazanolast Inhibits Ozone-induced Airway
Hyperresponsiveness in Guinea Pigs
ATSUSHI
IGARASHI,
HIDEYA
IIJIMA,
GEN
TAMURA,
and
KUNIO
SHIRATO
First Department of Internal Medicine, Tohoku University School of Medicine, Sendai, Japan
We studied the inhibitory effect of tazanolast, a selective mast-cell-stabilizing drug, on ozone-induced
airway hyperresponsiveness in guinea pigs. Airway responsiveness to methacholine peaked at 2 h after ozone exposure (2.0 ppm for 2 h) and the number of neutrophils in bronchoalveolar lavage (BAL)
fluid continued to increase until 6 h. Tazanolast administered before ozone exposure at doses of 30, 100, or 300 mg/kg inhibited ozone-induced airway hyperresponsiveness in a dose-dependent manner. However, tazanolast administered after ozone exposure did not inhibit the airway hyperresponsiveness. Tazanolast did not significantly change the cell distribution of BAL cells at 2 h after the exposure. We conclude that tazanolast significantly inhibits ozone-induced airway hyperresponsiveness in guinea pigs. This result suggests that mast cells may play an important role in its development.