β3肾上腺素能受体对大鼠梗死心肌保护作用的研究

Change and Effect of β3-Adrenoreceptor in Rats with Myocardial Infarction

目的:探讨心肌梗死大鼠梗死心肌中β3肾上腺素能受体(β3-Adrenoreceptor,β3-AR)表达的变化及其是否对大鼠梗死心肌起保护作用。方法:将40只雄性SPF级SD大鼠随机分为假手术组(Sham组)、心肌梗死组(MI组)、MI+BRL组(经尾静脉注射β3-AR特异性激动剂BRL-37344)[4 nmol/(kg.min),10 min,3次/周,共3周]、MI+SR组(经尾静脉注射β3-AR特异性拮抗剂SR59230A)[0.56 mg/(kg.min),10 min,3次/周,共3周]。采用超声心动图检测心脏参数;采用Masson染色检测梗死区心肌纤维化程度及TUNEL染色检测梗死区心肌细胞的凋亡水平。结果:MI+BRL组大鼠LVEF较MI组显著升高(45.17±8.98 vs. 34.93±4.08,P<0.05);MI+BRL组大鼠梗死区心肌细胞的凋亡水平较MI组显著减轻(16.236±1.76%vs. 28.336±2.33%,P<0.05);MI+BRL组大鼠心肌梗死区β3-AR mRNA表达较MI组明显增加(2.135±0.0235 vs. 1.690±0.012,P<0.05)。结论:心肌梗死大鼠模型中梗死区心肌β3-AR表达显著上调;β3-AR对梗死心肌有保护作用。

Objective:To investigate the change of β3-adrenergic receptor(β3-AR)expression in infarction myocardium and whether β3-AR plays a protective role in rats with myocardial infarction(MI). Methods:40 male rats were divided into the following four groups:Sham operated group(Sham group),MI group,MI+BRL group and MI+SR group.MI model was established by left anterior descending artery ligationy. The rats in the MI+BRL group received selective β3-AR agonist,BRL-37344 4.0[nmol/(kg.min),10 min,3 times per week for 3 weeks]via tail vein injection. The rats in the MI+SR group received selective β3-AR antagonist,SR59230 A[0.56 mg/(kg.min),10 min,3 times per week for 3 weeks]. Echocardiography was performed to measure the cardiac parameters. Masson.s trichrome staining was performed to observe fibrosis in infarction myocardium. Myocardial apptosis was detected by terminal deoxynucleltidyl transferase mediated dUTP nick-end labeling(TUNEL). Results:The LVEF in MI+BRL group were higher than MI group(45.17±8.98 vs. 34.93±4.08,P<0.05). Myocardial apoptosis in MI+BRL group were significantly lower than MI(16.236±1.76%vs. 28.336±2.33%,P<0.05). The levels of β3-AR m RNA expression in the MI+BRL group was obviously higher than MI group(2.135±0.0235 vs 1.690±0.012,P<0.05). Conclusions:The expression of β3-AR mRNA was upregulated in infarction myocardium in the rats with myocardial infarction. β3-AR plays a protective role in in rats with MI.