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Airway obstruction after acute ozone exposure in BALB/c mice using barometric plethysmography
An Soo Jang1, Inseon S Choi, Sun Wook Kim
1Department of Internal Medicine, Cheju National University College of Medicine, 154, Samdo-2-dong, Jeju-si, Jeju-do 690-716, Korea. jas877@chollian.net
Background:
Airway responsiveness after acute inhalation of ozone is related to the concentration and duration of ozone exposure. Using barometric whole-body plethysmography and increase in enhanced pause (Penh) as an index of airway obstruction, we measured the response of BALB/c mice to acute ozone inhalation to study the time course change of pulmonary function after ozone exposure.
Methods:
Penh was measured before and after exposure to filtered air or 0.12, 0.5, 1, or 2 ppm ozone for 3 hr (n = 6/group). In addition, Penh was measured 24, 48 and 72 hr after ozone exposure. Bronchoalveolar lavage (BAL) and histopathologic examinations were performed.
Results:
The increase in Penh after ozone exposure was significantly higher in the 0.12, 0.5, 1 and 2 ppm groups compared with the control group (all p < 0.01). Increases in Penh 24 hr after ozone exposure were significantly lower than those immediately after acute ozone exposure; however, increases in Penh 72 hr after ozone exposure were significantly higher than those in the control group (each p < 0.01). The proportion of neutrophils in BAL fluid was significantly higher in the group exposed to 2 ppm ozone than in the groups exposed to filtered air or 0.12 ppm ozone (both p < 0.01).
Conclusion:
These results indicate that airway obstruction is induced following ozone exposure in a concentration-dependent manner and persists for at least 72 hr.