中文摘要：

目的观察醛固酮对大鼠主动脉平滑肌鼠双微体-2基因（MDM2）表达的影响。方法将SD大鼠随机分为3组，每组8只。采用皮下给药的方法建立醛固酮增多症模型，其中醛固酮组经微量渗透泵持续释放醛固酮（1μg/h）；醛固酮＋螺内酯组除给予等量醛固酮外，每习行螺内酯灌胃（每13100mg／kg）；对照组仅泵空白溶剂。尾套法检测大鼠血压，4周后处死所有大鼠，测定血钾、钠、醛固酮浓度及血浆肾素活性。分别采用逆转录-聚合酶链反应（RT—PCR）、Westernblot、免疫组织化学检测主动脉平滑肌MDM2基因表达。结果（1）成功建立醛固酮增多症大鼠模型：醛固酮组2周后血压明显升高，血钾下降，呈现低。肾素、高醛固酮特征，与对照组比较差异有统计学意义（P〈0．01）；（2）醛固酮组主动脉平滑肌MDM2基因表达明显高于对照组（P〈0．01）。螺内酯可抑制醛固酮的上述作用（P〈0．01）。结论醛固酮可促进血管平滑肌细胞中MDM2的表达，而螺内酯可拮抗其效应。

英文摘要：

Objective To study the effect of aldosterone on murine double minute2 （ MDM2 ） gene expression in rat aortic smooth muscle ceils in vivo. Methods Sprague-Dawley rats （n = 8 in each group） were randomly assigned to receive one of the following combinations via a mini-osmotic pump for 4 weeks ： vehicle （60% propylene glycol ＋ 10% ethanol ＋ 30% ddH2O, V/V, subcutaneously）, aldosterone （1 μg/h, subcutaneously）, or spironolactone （100 mg/kg every day, gastric gavage） plus the equal doses of aldosterone. Systolic blood pressure was monitored by the tail-cuff method weekly. All animals were sacrificed 4 weeks later,then serum Na^＋ , K^＋, aldosterone and PRA were measured. The MDM2 gene expression in rat aortic smooth muscle ceils was detected by RT-PCR, Western blot and immunohistochemical staining. Results （ 1 ） The hyperaldosteronism models were successfully established. In aldosterone-infused group systolic blood pressure was markedly elevated, the serum levels of K^＋ and PRA were decreased, and plasma aldosterone level was increased as compared with controls （P 〈 0.01 ） ;（2） Aldosterone infusion could increase the MDM2 gene expression in rat aorta as compared with controls （P 〈 0.01 ）. All the above detrimental effects of aldosterone could be inhibited by spironolactone （ P 〈 0.01 ）. Conclusion Aldosterone promotes the expression of MDM2 gene in aortic smooth muscle cells in vivo, which can be inhibited by spironolactone.