【作者】 陆国军；

【导师】 王彤；

【作者基本信息】 南京医科大学 ， 呼吸内科学， 2008， 硕士

【摘要】 研究背景:支气管哮喘是世界范围内患病率和死亡率很高的慢性疾病之一,变态反应、气道炎症、气道高反应性及神经等因素及其相互作用被认为与哮喘的发病关系密切。在受体方面,有关β₂-AR、M受体、糖皮质激素受体的研究很多,这些在哮喘的发病、治疗中起着不同的重要作用。近有研究显示,哮喘患者外周血液中可见AngⅡ升高,AT₁R拮抗剂有降低哮喘模型支气管肺泡灌洗液中细胞数,减轻气道反应性作用,且AT₁R拮抗剂有抑制慢性哮喘气道炎症,减轻气道阻力作用,提示AngⅡ及其受体参与了哮喘的发病。但有关哮喘中肺组织ATR的表达,ATR与其他受体之间的互相影响鲜见有报道。本文拟通过研究AT₁R拮抗剂缬沙坦对哮喘大鼠模型干预后大鼠肺组织中ATR和β₂-AR的表达变化,进一步探讨AngⅡ及其受体在慢性哮喘发病中的作用和机制。目的:探讨哮喘大鼠肺组织中血管紧张素Ⅱ（AngⅡ）两种受体亚型（AT₁R、AT₂R）和β₂肾上腺素受体（β₂-AR）的表达及缬沙坦对两类受体的影响。方法:将50只SPF级Wistar大鼠按随机数字法分为5组（n=10）,分别为正常对照组（A组）、哮喘组（B组）、缬沙坦15mg/kg组（C₁组）、缬沙坦30mg/kg组（C₂组）、缬沙坦50mg/kg组（C₃组）。用10%鸡卵白蛋白（OVA）致敏和1%OVA激发大鼠建立哮喘模型;分别用逆转录-聚合酶链反应（RT-PCR）和Western blot法检测肺组织中ATR和β₂-AR mRNA和蛋白表达;用原位杂交法检测肺组织中ATR和β₂-AR mRNA的分布情况;用Western blot法各组肺组织中转录活化因子-3（STAT3）基因的表达。结果:①与A纽相比,B组的AT₁R阳性表达率明显增高（P＜0.05）。缬沙坦干预后,C₁、C₂、C₃组的AT₁R阳性表达率均明显下降（P均＜0.05）;相关性分析提示AT₁R的表达与缬沙坦剂量呈负相关（r=-0.96）。②A组未见AT₂R表达,B组AT₂R表达明显增加。缬沙坦干预后,C₁组无AT₂R表达,C₂、C₃组AT₂R表达量低于B组（P均＜0.01）。③与A组相比,B组的β₂-AR阳性表达率明显下调（P＜0.01）,缬沙坦干预后,C₁、C₂、C₃组的β₂-AR阳性表达率均明显上调（P均＜0.05）。④与A组相比,B组的STAT3阳性表达率明显增高（P＜0.05）。缬沙坦干预后,C₁、C₂、C₃组的STAT3阳性表达率均明显下降（P均＜0.05）。结论大鼠肺组织中存在血管紧张素Ⅱ受体,并在哮喘发作时被活化,可能参与哮喘发病的病理生理过程。ATR与β₂-AR的变化可能存在相关性。哮喘大鼠肺组织中AT₁R和AT₂R表达增加,β₂-AR表达下调。AT₁R拮抗剂缬沙坦能抑制AT₁R表达,上调β₂-AR表达。AngⅠ的可能作用途径之一是通过STAT3信号通路。更多还原

【Abstract】 Background:Asthma is one of the high morbidity and mortality rate diseases over the world,aeroallergen、airway inflammation、high airway reactive、nervous factors and their interaction are highly related with the progress of asthma.As receptors,they are many research onβ₂-AR、M receptor、glucocorticoid receptor,which play an important part in the morbidity and treat of asthma.Recent research indicate that the incereased AngⅡcan be found in the peripheral blood of asthmatic patients.The antagon of AT₁R have the action of decrease the cell number in bronchoal veolar lavage fluid（BALF）and relieve airway reactive.Moreover,the antagon of AT₁R can improve airway inflammation and relieve airway resistance,which suggests AngⅡand its receptors participate the progress of asthma.However,there is few report about the expression of ATR,how ATR interaction with other receptors in the lung. By intervention on asthmatic rat samples with valsartan,this article is designed to study the expression ATR andβ₂-AR,also the action and mechanism of AngⅡand its receptors in the chronic asthma.Objective:To investigate the expression of angiotensinⅡreceptor subtypes （AT₁R,AT₂R）andβ₂- adrenergic receptor（AR）in the lungs of asthmatic rats, and the influence of valsartan upon their expression.Methods:Fifty Wistar rats were randomly divided into 5 groups,group A （control）,group B（asthma）,group C₁（Valsartan 15mg/kg）,group C₂ （Valsartan 30mg/kg）,group C₃（Valsartan 50mg/kg）,each containing 10 subjects.The rats were sensitized by 10%ovalbumin peritoneal injection and challenged by 1%ovalbumin aerosol inhalation to establish the asthmatic model.The levels of AT₁R,AT₂R andβ₂-AR mRNA and protein in lung tissues were analyzed by reverse transcriptase-polymerase chain reaction（RT-PCR） and Western blot.Results:①Comparing with control（group A）,the expression levels of AT₁R in asthmatic subjects（group B）was significantly increased（P＜0.05）. Valsartan decreased the level of AT₁R in asthmatic groups（group C₁,C₂ and C₃）.A negative correlation between the expression of AT₁R and the dose of valsartan was demonstrated（r=-0.96）.②There was no AT₂R expression in control（group A）,while in asthmatic subjects（group B）the AT₂R expression increased markably.By the use of valsartan,the elevated level of AT₂R either could not be found（group C₁）or markedly decreased（group C₂ and C₃）;③Comparing with control（group A）,theβ₂-AR level in asthmatic subjects （group B）was significantly decreased（P＜0.01）.By the use of valsartan,the positive expression rate ofβ₂-AR increased in group C₁、C₂ and C₃ compared with group B（P＜0.05,respectively）;④Comparing with control（group A）,the expression levels of STAT3 in asthmatic subjects（group B）was significantly increased（P＜0.05）.Valsartan decreased the level of STAT3 in asthmatic groups（group C₁,C₂ and C₃）.Conclusions:The results suggest that angiotensinⅡreceptors（ATR）are expressed in rat lung tissues.The ATR may be activated and play a role in asthma attack.The expression and the function of ATR in the asthmatic rats lung may be related with the change ofβ₂-AR.The expression of AT₁R and AT₂R in the asthmatic rats lung were increased,whileβ₂-AR decreased. Valsartan can inhibit the expression of AT₁R and restore the expression ofβ₂-AR.One possible pathogenes of AngⅡis by STAT3 pathway.更多还原