地塞米松对气压创伤性中耳炎模型大鼠中耳黏膜上皮钠通道mRNA转录的影响  

Dexamethasone Can Raise the Expression of ENaC in Middle Ear Mucosa of Barotrauma-induced Otitis Media in Rat

作　　者：宗雨[1,2] 李祥翠 张奕[1,2] 李吉平 

机构地区：[1]上海交通大学医学院附属仁济医院耳鼻咽喉头颈外科 [2]上海交通大学(医学院)耳鼻咽喉科研究所,上海200127

出　　处：《听力学及言语疾病杂志》2013年第2期155-158,共4页Journal of Audiology and Speech Pathology

摘　　要：目的探讨地塞米松对气压创伤性中耳炎模型大鼠中耳黏膜中上皮钠通道(epithelial sodium channel,ENaC)转录的影响。方法 18只清洁级SD大鼠随机分为为干预组、模型组及正常对照组,每组6只(12耳)。正常对照组未予任何处理,干预组及模型组通过增加环境气压制作气压创伤性中耳炎模型,干预组在造模后连续三天腹腔注射地塞米松(2mg/kg,加入生理盐水0.5ml)。在造模后第1、3、7天分别观察各组鼓膜形态变化;在造模后第七天取中耳黏膜,采用实时定量-聚合酶链反应(real time-polymerase chain reaction,Real time-PCR)检测各组大鼠中耳黏膜中ENaC转录情况。结果对照组大鼠各时间段鼓膜均未见明显异常。模型组第1天每只大鼠至少有一耳鼓室内充满琥珀色积液,鼓膜充血,松弛部膨出,可见小气泡;第3天时鼓室仍有琥珀色积液,以上鼓室为著,松弛部内陷,气泡消失;第7天时未见鼓室积液,鼓膜亦基本恢复正常。干预组第1天每只大鼠至少有一耳可见鼓室内充满琥珀色积液,鼓膜充血,松弛部膨出,可见小气泡;第3天时所有大鼠双耳均未见明显鼓室积液征,鼓膜浑浊;第7天时未见鼓室积液,鼓膜亦基本恢复正常。干预组大鼠中耳黏膜α-ENaC-mRNA、β-ENaC-mRNA、γ-ENaC-mRNA均上调,分别为模型组的2.04、2.56、2.00倍(P<0.01)。结论地塞米松能加速气压创伤性中耳炎模型大鼠中耳腔内积液的清除,增加ENaC在中耳黏膜中的基因转录,可能是糖皮质激素清除中耳腔积液的机制之一。Objective To investigate the effect of dexamethasone on the expression of ENaC in middle ear mucosa of barotrauma--induced otitis media in rat. Methods Eighteen SD rats were randomly divided into interven- tion group, model group and normal control group. Intervention group and model group were barotraumatic--in- duced otitis media models by increasing ambient air pressures After building the model ,intervention group was giv- en,intravenous injection of dexamethasone（2 mg/kg, add to 0.5 ml normal saline） ,on three consecutive days. On day 7, the rats were sacrificed and the middle ear mucosa were collected. Real--time polymerase chain reaction were done for expression analysis of ENaC-- （x , --13 , -- 7. Results 1. In the model group,on day existence of effusion and the erythena of tympanic membrane were observed at least in one ear,On day 3 there was amber effusiomOn day 7, middle ear effusion disappeared and tympanic membrane restored to normal. In the intervention group, on day 1, some results were observed as in the model groups On day 3, all rats showed no obvious effusion syndrome. On day 7, tympanic membrane restored to normal. 2. The level of α- ,β- ,γ-ENaC-mRNA transcription in the intenention group increased 2.04-- ,2.56-- ,2.00--fold compared with those of in the model group（n=6,P〈0.01） in the mid- dle ear mucous after dexamethasonetreated. Conclusion Dexamethasone can accelerate fluid clearance in the middle ear cavity and increase the transcription of ENaC in the middle ear mucosa in rat model of barotramauma--induced o titis media model. This may be one of the mechanisms of glucocorticoid clearance of middle ear effusion

关 键 词：上皮钠通道 动物模型 气压创伤性中耳炎 地塞米松 实时定量 聚合酶链反应 

分 类 号：R764.21[医药卫生—耳鼻咽喉科]