The mainstream and sidestream cigarette smoke are the active and passive form respectively. Tabagism is the main cause of chronic obstructive pulmonary disease (COPD). Acute exposure of mice to cigarette smoke can induce neutrophilic and macrophagic lung infiltration as described in the natural human disease. However, the responses of animals depend on exposure conditions. The aim of this study was to compare the responses of mice to different conditions of cigarette smoke exposure through various smoking systems.

The exposure of mice to a mixture of mainstream and sidestream filtered cigarette smoke at 3 levels of concentrations (1, 2 or 3 cigarettes/9 min), 6 h/day for 1, 2, 3, 4 or 5 days using a Teague Smoking Machine (Volume chamber: 264L) didn't change the number of neutrophiles in the bronchoalveolar lavage (BAL). In another smoking machine, mice were only exposed to mainstream of filtered or non-filtered cigarette smoke directly introduced in a 5L exposure chamber (1 cig/5 min, 2 h/day for 3 days). Only the non-filtered cigarette smoke induced a significant increase of neutrophiles in the BAL (Air exposed mice: 1000  1163 vs. Cigarette smoke exposed mice: 52900  27011 neutrophiles/mL). These exposure conditions have been confirmed in a modified Teague Smoking Machine using only mainstream cigarette smoke of 8 non-filtered cig/9 min, 2 h/day for 1 day. The number of neutrophiles was significantly increased (0  0 vs. 32933  14593 neutrophiles/mL). Mice didn't develop any clinical signs linked to cigarette smoke exposure.

In conclusion, exposure of mice to high concentrations of mainstream and non-filtered cigarette smoke induced a significant neutrophilic infiltration in BAL fluids.