Effects of ozone on influenza virus-induced airway hyperreactivity in rats

Lee, Hye Kyung

Abstract

BACKGROUND
Ozone is one of the most ubiquitous oxidant in urban air and may exacerbate respiratory diseases such as asthma.
OBJECTIVE
We examined whether ozone can influence airway hyperresponsiveness induced by influenza virus-infection. SUBJECT AND METHOD: Rats were exposed to ozone, acutely to 1.0ppm and 0.25ppm for 23.5hrs. At 2hrs post cessation of ozone exposure, animals were infected with rat-adapted influenza virus intra-nasally. On day 3 post-virus inoculation, pulmonary mechanics were measured during an intravenous challenge with acetylcholine < (ACh), 100-140mg/ml in saline>. Cumulative doseresponse functions were obtained by doubling the rate of the intravenous infusion every 2min.
RESULTS
ACh increased airway resistance in a dose-dependent manner. Neither of the concentrations of ozone altered the airway responses to ACh. Animals infected with virus developed hyperresponsiveness to ACh as was expected. Pre-exposure to 1.0ppm ozone for 23.5hrs aug- mented the virus-induced airway hyperresponsiveness, while 0.25ppm did not.
CONCLUSION
Acute exposure to ozone can synergistically act on virus-induced airway hyperreactivity.