[The effect of locally injected betamethasone on collagen deposition in benign central airway stenosis]. 
To assess the effects of locally injected betamethasone on cicatricial tissue hyperplasia in patients with benign central airway stenosis.  A prospective study was conducted with 2 treatment modalities: conventional interventional(CI)therapy, and CI combined with local betamethasone injection(LBI).  The average optical density value of TGF-β1 and collagen density in the local airway tissues were compared before therapy and 7 d after the CI treatment and the LBI treatment, respectively.  Six patients were recruited in this study from May 2013 to June 2015.The results showed significant statistical differences by paired t-test in TGF-β1: 92±38 vs 164±47(t=-7.984, P=0.000)before and after the CI treatment, respectively; 128±45 vs 78±40 (t=10.055, P=0.000)before and after the LBI treatment, respectively.  The collagen density was 91 932±59 520 vs 150 252±76 673(t=-8.105, P=0.000) before and after the CI treatment, respectively; 107 024±54 880 vs 114 038±50 772(t=-0.621, P=0.54) before and after the LBI treatment, respectively. Trend comparisons made before and after the treatments showed significant statistical differences in TGF-β1(F=712.139, P=0.000) and in the collagen density (F=261.256, P=0.000)between the CI treatment and the LBI treatment groups.  The CI treatment was shown to stimulate the production of TGF-β1 and the deposition of collagen, while the LBI treatment was shown to reduce the production of TGF-β1 and alleviate the deposition of collagen from the stimulation of the CI treatment.