Elastase-induced COPD.

Mice were injected (i.n.) with 0.5 μg elastase from porcine pancreas (Sigma-Aldrich, catalog E1250) in 50 μL of saline once per week for 4 consecutive weeks. BAL cell counting and lung tissue collection were performed 24 hours after the last elastase administration. DEX (0.3 mg/kg per mouse, i.p.) and C3G (200 μg i.p. and 100 μg i.n. per mouse) were administered to mice 1 hour before each elastase treatment and every other day between each elastase treatment. Airway space enlargement was measured as mean linear intercept (MLI) by ImageJ (NIH) in 20 randomly selected fields.