In patients with COPD, it is well known that the combination of
β2-adrenoceptor agonists with anticholinergic agents exhibits synergistic
effects on bronchodilation to improve lung function without
additional side effects (Hanania, Donohue 2007). Recently, the
combination of ICS with both types of bronchodilators is revealed to
be more effective in controlling the COPD symptoms (Aaron et al.,
2007; Welte et al., 2009). The present study showed a synergistic inhibition on the total cell and neutrophil counts in bronchoalveolar
lavage fluid as well as on the increased MMP-9 activity associated
with a reduced airspace enlargement. Though microscopic examination
observed significant reduction of alveolar sizes, the less obvious
but significant decrease in mean linear intercept is likely due to the
limits of this index which can have a low sensitivity when emphysema
is mild and not homogenous (Parameswaran et al., 2006). In
literature, similar differences between mean linear intercept measured
in healthy and emphysematous subject are recorded. While
emphysema is clearly detected, the difference of mean linear intercept
can remain rather limited (Thurlbeck, 1967). To the best of our
knowledge, this is the first report concerning the synergistic effects of
β2-adrenoceptor agonists combined with anticholinergic agents on
the chronic pulmonary inflammation and the airspace enlargement in
an animal model.