地塞米松对哮喘大鼠肺组织ADM及基因表达的影响

目的： 探讨地塞米松(DEX)对哮喘大鼠肺组织肾上腺髓质素(ADM)及基因表达的影响。方法: 选择30只雄性SD大鼠随机分为3组，每组10只。采用卵蛋白皮下注射及雾化吸入制成大鼠哮喘模型；采用逆转录聚合酶链反应(RT-PCR)法检测各组肺组织ADM的mRNA表达水平，同时用免疫组化方法检测ADM表达水平，并在光镜下观察支气管壁厚度(WA/Pi)、支气管平滑肌厚度(平滑肌面积/Pi)及肺组织形态学改变。结果: 哮喘组(A组)ADM的mRNA和蛋白表达明显高于对照组(C组)(P<0.05)；治疗组（B组）ADM的mRNA和蛋白表达进一步增加，明显高于哮喘组(A组)(P<0.01)。结论: 地塞米松促进肺组织ADM表达升高，可能是其治疗哮喘的机制之一。

Effect of dexamethasone on the adrenomedullin and its gene expression in lung tissue of asthmatic rats

AIM: To study the effect of dexamethasone (DEX) on the adrenomedullin (ADM) and its gene expression in lung tissue of asthmatic rats. METHODS: 30 healthy male SD rats were randomly divided into three groups (10 for each). The asthmatic model was established by ovalbumin inhalation and injection. The mRNA expression of ADM was examined by RT-PCR and the protein expression was detected by immunohistochemical method. The airway wall thickness, the airway smooth muscle (ASM) thickness and pulmonary tissue changes were observed under light microscope. RESULTS: The expression of ADM mRNA and protein in the asthma group A were higher than those in the control group(group C) (P<0.05), indicating that the moderate expression of ADM in asthmatic rat lung tissue is compensatory. The expression was significantly higher in DEX group (group B) than that in group A (P<0.01), indicating that DEX stimulated the expression of ADM mRNA and protein in lung tissue of asthmatic rats. CONCLUSION: The remarkable expression of ADM after the therapy of dexamethasone is one of its therapeutic mechanisms.