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目的:研究心肌梗死后心力衰竭大鼠左心室非梗死区β受体密度和 mRNA表达的变化,同时观察卡维地洛和美托洛尔两类不同的β受体阻滞剂对其影响。方法:结扎大鼠冠状动脉前降支,形成广泛前壁心肌梗死,而后经过4周的左室重构,导致心力衰竭形成。手术组死亡率为43%,假手术组死亡率为4.7%。实验分为 4周和12周2个时间点进行。取手术组存活的50只大鼠随机分为 5 组:4 周手术(4O)组,美托洛尔 20 mg(M20)组,卡维地洛10 mg(C10)组,卡维地洛1 mg(C1)组,12周手术(12O)组;取假手术组存活的 20 只大鼠随机分为 2组:4周假手术(4S)组,12 周假手术(12S)组;每组均为 10 只大鼠。另外取 10 只正常大鼠作为 4 周正常对照(4N)组。M 20、C10和C1 组于术后4周开始给药;各组大鼠分别于术后4、12周取左心室非梗死区心肌,测定β受体密度及β1 和β2 受体mRNA。结果:4周时,心力衰竭组β受体密度(P<0.01)和β1 受体 mRNA表达(P<0.05)显著降低。12周时,美托洛尔显著增加β受体密度(P<0.01)和β1 受体 mRNA表达(P<0.05),卡维地洛没有增加β受体密度和β1 受体 mRNA表达的作用。结论:心力衰竭时β受体密度和β1 受体 mRNA表达降低,卡维地洛对β受体密度和β1 受体mRNA表达没有明显影响,而美托洛尔可明显增加心力衰竭大鼠β受体密度和β1
Objective: To study the changes of β -receptor density and mRNA expression in left ventricular non-infarcted area in rats with heart failure after myocardial infarction, and to observe the effects of different types of β-blockers including carvedilol and metoprolol. Methods: Ligation of anterior descending coronary artery in rats, the formation of extensive anterior myocardial infarction, and then after 4 weeks of left ventricular remodeling, leading to heart failure. Surgical mortality was 43%, sham operation mortality was 4.7%. The experiment was divided into 4 weeks and 12 weeks for 2 time points. Fifty rats survived in the operation group were randomly divided into 5 groups: 4-week surgery (20), metoprolol 20 mg (M20), carvedilol 10 mg The rats in the sham operation group were randomly divided into 2 groups: 4 weeks sham operation (4S) group, 12 weeks sham operation (12S) group; each group All 10 rats. In addition, 10 normal rats were taken as a 4-week normal control (4N) group. M20, C10 and C1 groups began to be administered at 4 weeks after operation. The myocardium of left ventricular non-infarcted area was taken at 4 and 12 weeks after operation in rats in each group, and β receptor density and β1 and β2 receptor mRNA were measured. Results: At 4 weeks, β receptor density (P <0.01) and β1 receptor mRNA expression (P <0.05) decreased significantly in heart failure group. At week 12, metoprolol significantly increased β -receptor density (P <0.01) and β1receptor mRNA expression (P <0.05), while carvedilol did not increase βreceptor density and β1receptor mRNA expression. CONCLUSION: β -receptor density and β1 -receptor mRNA expression are decreased in heart failure, while carvedilol has no obvious effect onβ-adrenoceptor and β1 -receptor mRNA expression, while metoprolol can significantly increase β-receptor in heart failure rats Body density and β1