Effect of the Chinese herbal medicine, Bakumondo-to, on airway hyperresponsiveness induced by ozone exposure in guinea-pigs.
OBJECTIVE
Bakumondo-to (Maimendong tang) is a Chinese herbal medicine that has been used as an anti-tussive agent. However, the effects of Bakumondo-to on airway hyperresponsiveness are unknown. We examine whether Bakumondo-to can inhibit airway hyperresponsiveness induced by ozone.


METHODS
Measurements of airway responsiveness and plasma extravasation and bronchoalveolar lavage (BAL) were performed before and after ozone exposure (3 p.p.m., 2 h). Guinea-pigs were anaesthetized with pentobarbital sodium and mechanically ventilated. Airway responsiveness was determined by an inhalation of doubling concentration of histamine, and the concentration of histamine required to produce a 200% increase in R(L) (PC200) was calculated by log-linear interpolation. Plasma extravasation was evaluated by measuring the extravasation of Evans blue dye in the airway.


RESULTS
Ozone produced significant airway hyperresponsiveness and plasma extravasation, with an influx of neutrophils in BAL fluid. Bakumondo-to (400 mg/kg p.o.) significantly inhibited airway hyperresponsiveness, but had no effect on neutrophil influx or plasma extravasation.


CONCLUSIONS
We demonstrated that Bakumondo-to can attenuate airway hyperresponsiveness induced by ozone without affecting airway inflammation, which suggests that Bakumondo-to may act on the subsequent mechanisms after the induction of inflammation, such as mediator release.
Aizawa
H
H
Clinical Research Institute, National Fukuoka-Higashi Hospital, Koga, Japan. aizawa@fukuokae.hosp.go.jp
Shigyo
M
M
Nakano
H
H
Matsumoto
K
K
Inoue
H
H
Hara
N
N
D000403:Airway Resistance / Q000187:drug effects; D000704:Analysis of Variance; D000818:Animals; D016535:Bronchial Hyperreactivity / Q000139:chemically induced / Q000188:drug therapy*; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D002463:Cell Membrane Permeability / Q000187:drug effects; D004195:Disease Models, Animal; D004365:Drugs, Chinese Herbal / Q000008:administration & dosage* / Q000493:pharmacokinetics; D006168:Guinea Pigs; D008168:Lung / Q000187:drug effects / Q000502:physiology; D008297:Male; D010126:Ozone; D011897:Random Allocation; D012016:Reference Values; D018709:Statistics, Nonparametric
D004365:Drugs, Chinese Herbal; D010126:Ozone