压力负荷及容量负荷性肥厚心肌中血管紧张素Ⅱ-1型受体mRNA表达的变化

EXPRESSION OF ANGIOTENSIN TYPE1 RECEPTOR SUBTYPES mRAN IN MYOCARDIAL HYPERTROPHY CAUSED BY PRESSURE AND VOLUME OVERLOAD

采用腹主动脉缩窄（ＡＣ）及腹腔动－静脉瘘（ＡＣＦ）分别制造大鼠压力负荷及容量负荷增加所致心肌肥厚模型，应用反转录－聚合酶链式反应（ＲＴ－ＰＣＲ）及同位素掺入技术，比较两种模型在术后不同时间点左、右心室组织中ＡｎｇⅡ－１型受体ａ亚型（ＡＴ１ａ）及ｂ亚型（ＡＴ１ｂ）ｍＲＮＡ的表达及其与心肌肥厚的关系。发现ＡＣ组术后３天左室／体重比（ＬＶ／Ｂｗｔ）尚未发生显著性变化，而左室组织中ＡＴ１ｂｍＲＮＡ的表达已明显升高（Ｐ＜０．０１ｖｓＳＯ）。术后１２天、３５天左室肥厚进行性加重，左室组织中ＡＴ１ａｍＲＮＡ和ＡＴ１ｂｍＲＮＡ的表达呈进行性升高；而右室中ＡＴ１ａｍＲＮＡ及ＡＴ１ｂｍＲＮＡ表达始终未见升高。且右室／体重比（ＲＶ／Ｂｗｔ）也始终无显著性改变。ＡＣＦ组术后３ｄ，ＲＶ／Ｂｗｔ、ＬＶ／Ｂｗｔ已显著升高，而左、右心室中ＡＴ１ａｍＲＮＡ及ＡＴ１ｂｍＲＮＡ表达尚未见显著性升高；术后１２ｄ、３５ｄ右室、左室肥厚更为明显，左、右心室组织中ＡＴ１ａｍＲＮＡ及ＡＴ１ｂｍＲＮＡ表达呈进行性升高。提示心肌ＡＴ１受体基因表达的变化，参与机械负荷性心肌肥厚的发生、发展，且压力负荷及容量负荷性肥厚心肌中ＡＴ１ｍＲＮＡ表达间的差异，可能是两种?

In this study, myocardial hypertrophy caused by pressure overload (aortaconstruction,AC) and volume overload (Aortocaval fistula ACF) were duplicated on male rats ,and then we examined the expression of AT1amRNAAT1bmRNA both in left and right ventricle during different times after operation by reverse transcriptionpolymerase chain reaction(RTPCR),and isotope incorporation, in order to compare with this tow models.We found that 3 days after AC the expression of AT1bmRNA increased significantly (P<0.01 vs SO);12 days and 35 days after operation the expression of AT1amRNA and AT1bmRNA in left ventricle increased permanently with the rising of cardial mass, while the expression in right ventricle remained unchanged.3 dyas after ACF,the expression both in left and right ventricle increased obviously;12 days and 35 days after operation the expression in double ventricles increased continuously.The results suggests that the change of mRNA expression of AT1 receptor involves in the development of myocardial hypertrophy, and the difference expression of AT1 receptor between myocardial hypertrophy caused by pressure and by volume overload may be one of the reasons.The development of myocardial hypertrophy caused by pressure are different with hypertrophy by volume overload.