Effect of Dexamethasone on the Cellular DNA Synthesis and Remodelling of Airway in Asthmatic Rats

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). Results① 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)(P0.01). 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)(P0. 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.