The anti-inflammatory properties of inhaled formoterol and ipratropium bromide, alone or in combination,
were investigated in a rat model of chronic pulmonary inflammation with airspace enlargement induced by
cadmium inhalation. At the end of the protocol, cadmium-induced increase of airway resistance was
prevented by formoterol (4 mg/30 ml) or ipratropium (0.20 mg/20 ml). Formoterol elicited a significant
decrease in total cell and neutrophil counts in bronchoalveolar lavage fluid as well as on the activity of
gelatinase B (MMP-9), an enzyme strongly expressed in alveolar macrophages and epithelial cells.
Additionally, a significant attenuation of the lung lesions characterized by inflammatory cell infiltration
within the alveoli and the interstitium and a decrease in mean linear intercept were observed. Although
ipratropium alone had no effects on the cadmium-induced pulmonary inflammation and emphysema, its
combination with an inefficient concentration of formoterol (1 mg/30 ml) showed a synergistic inhibitory
effect on neutrophil and total cell counts as well as on the mean linear intercept associated with a synergistic
inhibition on the MMP-9 activity. Gelatinase A (MMP-2) activity was not influenced by drug pretreatments.
Neither macrophage metalloelastase (MMP-12) activity nor levels of cytokines IL-1β, TNF-α and GM-CSF in
bronchoalveolar lavage fluid were modified in rats chronically exposed to cadmium. No desensitization of
β2-adrenoceptors or cholinergic receptors on airway smooth muscles and inflammatory cells during the
protocol was observed. In conclusion, formoterol alone or combined with ipratropium bromide partially
protects the lungs against the chronic inflammation and airspace enlargement by reducing neutrophilic
infiltration possibly via the inhibition of MMP-9 activity.