运动性和高血压性肥大心脏心肌内皮素及其基因表达的研究

Expression of Endothelin-1 and Its Gene in Myocardium of Exercise-induced and Hypertensive Hypertrophied Heart

近年来发现内皮素 (ET1)除具有强大的缩血管作用外 ,还是一个强大的致心肌肥大活性因子。为探讨(ET1)在运动性心肌肥大形成中的作用 ,本实验采用免疫组化和Northern分子杂交方法 ,对游泳运动大鼠和自发性高血压大鼠 (SHR)心肌细胞ET1分布及其基因表达进行研究。结果表明 :大鼠经 10周游泳运动后心肌细胞ET1分布和mRNA表达均比安静对照大鼠增加 ,但比安静SHR心肌细胞ET1分布和mRNA表达减少 ;SHR经 10周游泳运动后 ,心肌细胞ET1分布和mRNA表达均比安静SHR明显降低。这些结果提示 :( 1)ET1参与运动性心肌肥大形成机制 ,并在其变化特征上与高血压肥大心脏不同 ;( 2 )运动使高血压肥大心肌细胞ET1分布减少 ,在减轻ET1对肥大心脏的损伤作用方面可能具有积极意义 ;( 3 )运动可在基因转录水平上调节心肌细胞内ET1分布变化。

Effectsofendothelin - 1(ET1) -inducedproteinsynthesisandimmediategeneexpressiononcardiomyocyteshavebeenidenti fiedrecently ,buttheeffectsofET1inmyocardiumofexercise -inducedandhypertensivehypertrophicheartwereunclear Wethere forestudiedtheET1immunoreactivityanditsgeneexpressioninmyocardiumofWistarratsandspontaneouslyhypertensiverats (SHR) subjectedto 10 -weekswimmingprogrambyimmunohistochemistryassayandNorthernbolt TheresultofNorthernboltwasanalyzed byscanningdensitometry ThemyocardiumintracellularET1immunoreactivityofswimmingratswasstrongerthanthatofWKYratsbut theimmunoreactivityofsedentarySHRwasstrongestinthethreegroups TheexpressionsofET1mRNAinmyocardiumwereincreased 1 7foldsinswimmingratsand 2 1foldsinSHRrespectivelybyscanningdensitometry,comparedwithWKYrats AfterSHRswim mingfor 10weeks,theintracellularET1immunoreactivityfellobservablyandtheexpressionofET1mRNAwasdecreasedby 19% thanthatofsedentarySHR Theresultssuggestthat:( 1)increaseofET1immunoreactivityinmyocardiumofswimmingratsmayplay animportantroleinexercise -inducedhypertrophicheart;( 2 )decreaseofET1immunoreactivityinmyocardiumofswimmingSHR seemsreasonabletodecreasingeffectofET1damageonhypertrophicmyocardium ;( 3 )intracellularET1immunoreactivityofexercise - inducedandhypertensivehypertrophicheartcanberegulatedingenetranscriptionlevelbyexercise