目的  观察地塞米松对实验性哮喘大鼠气道细胞ＤＮＡ合成和气道重塑的干预效果。 方法   应用ＳＤ大鼠建立哮喘动物模型，采用免疫组化技术和其它形态学研究的方法，研究雾化吸入地塞米松对气道细胞ＤＮＡ合成和气道重塑反应的影响。 结果   ① 地塞米松治疗组气道上皮下胶原沉积以及粘液的分泌比模型组明显减少。② 模型组气道平滑肌细胞Ｂｒｄｕ阳性计数（１０．２５±２．０９）明显高于正常对照组（７．１５±２．０５）和地塞米松治疗组（６．８５±２．２０）（Ｐ＜０．０１）；模型组气道上皮细胞Ｂｒｄｕ阳性计数（２１．８３±７．０１）亦明显高于正常对照组（１６．２２±４．３６）和地塞米松治疗组（１６．９２±３．４８）（Ｐ＜０．０５）。 结论  应用地塞米松干预可减轻实验性哮喘大鼠气道炎症，抑制气道细胞ＤＮＡ合成，延缓气道重塑反应的发生。

OBJECTIVE: To study the effect of dexamethasone(DXM) on the cellular DNA synthesis and airway remodelling of airway in asthmatic rats. METHODS: Asthmatic model was established using SD rats. The changes of the airway wall were observed by coll agen and mucus staining and Bromodeoxyuridine(Brdu)-positive cells were detecte d using immunohistochemical technique in the airway smooth muscle(ASM) and epit heli um in the asthmatic model rats(model group), DXM inhalation rats(DXM group), a nd normal rats(control group). RESULTS: ① The collagen d eposition in the subepithelium and mucus staining in the airway obviously decreased in the DXM group compared with the model group.②The Brdu-positive cells of ASM in the model group(10.25±2.09) were significantly higher than those in the control group(7.15±2.05) and the DXM group(6.85±2.20)(P<0.01). The Brdu-positive cells of the epithelium in the model group(21.83±7.01) were also significantly higher than those in the control group(16.22±4.36) and the DXM group(16.92±3.48)(P<0. 05). CONCLUSIONS: Inhaling DXM may alleviate airway inflammation response, inhib it DNA synthesis of airway cells and prevent from developing airway remodelling in asthmatic rats.