ABSTRACT
<p><b>OBJECTIVE</b>To investigate the effect of bicuculline, a selective GABAA receptor antagonist, on airway remodeling in the murine model of chronic allergen-induced asthma.</p><p><b>METHODS</b>Forty BALB/C mice were randomized into 4 groups, namely the control group, asthmatic model (induced by ovalbumin sensitization and challenge) group, budesonide inhalation group and bicuculline inhalation group. The mice were sacrificed 24 h after the last ovalbumin inhalation, and the lungs were lavaged with PBS and the total cells, eosinophils and lymphocytes counts were examined. Periodic acid-Schiff (PAS) staining was used for counting mucin-positive goblet cells in the lung tissue, and Masson Trichrome staining was used to evaluate collagen deposition. GABAARbeta2 and VEGF were quantified by immunohistochemistry.</p><p><b>RESULTS</b>The numbers of the total cells, eosinophils and lymphocytes counts in BALF were significantly greater in the bicuculline group than in the control and budesonide groups (P<0.01), but comparable to those in the asthmatic model group (P>0.05). The airway collagen deposition in the bicuculline group was comparable to that in the control and budesonide group (P>0.05), but was significantly less than that in the asthmatic model group (P<0.05). Significant differences were found in the airway histological mucus index between the bicuculline group and the other 3 groups (P<0.05). The airway GABAARbeta2-positive cell percentage in the bicuculline group was significantly greater that those in the control and budesonide (P<0.01 and 0.05), but similar with that in the asthmatic model group (P>0.05). The percentage of pulmonary perivascular VEGF-positive cells in the bicuculline group was significantly greater in the control and budesonide groups (P<0.01 and P<0.05), but comparable to that in the asthmatic model group (P>0.05).</p><p><b>CONCLUSION</b>GABAARbeta2 is expressed in both the airway epithelium and smooth muscles. Bicuculline inhalation can effectively suppress collagen deposition with a stronger inhibitory effect on mucus hypersecretion than budesonide.</p>