心衰大鼠心肌β_3肾上腺素能受体和内皮型一氧化氮合酶的表达

Change of expressions of β_3-adrenergic receptor and endothelial nitric oxide synthase in heart failure rats

目的检测从心肌肥大到心力衰竭的发展过程中大鼠心脏β3肾上腺素能受体(β3-adrenergicreceptor,β3-AR)和内皮型一氧化氮合酶(endothelial nitric oxide synthase,eNOS)表达水平的变化,为临床治疗心力衰竭提供新思路。方法成年雄性Wistar大鼠80只,随机分为正常对照组(n=10),模型组(n=70)。采用皮下注射盐酸异丙肾上腺素(170 mg.kg-1.d-1×4d)制备大鼠心力衰竭模型。存活的模型组大鼠分为心肌肥大1周组(myocardial hypertrophy 1 week group,MH1w),心肌肥大2周组(myocar-dial hypertrophy 2 week group,MH2w),心肌肥大3周组(myocardial hypertrophy 3 week group,MH3w),心肌肥大4周组(myocardial hypertrophy 4 week group,MH4w)和心力衰竭组(heart failure group,HF)。第1、2、3、4、6周末分别应用超声心动图检测各组大鼠左心室功能,确定模型制备成功。取大鼠心脏组织,透射电子显微镜观察心肌超微结构变化。TUNEL细胞凋亡检测试剂盒检测心肌细胞凋亡情况。West-ern blot检测β3-AR和eNOS等相关蛋白的表达。结果与对照组比较,心力衰竭组大鼠射血分数(leftventricular ejection fraction,LVEF)明显降低(P<0.01);注射盐酸异丙肾上腺素1周后,左室后壁舒张期厚度(left ventricular posterior wall dimensions,LVPWd)明显增加,3周后LVPWd开始下降,4周后LVPWd接近正常水平;心肌细胞凋亡率逐渐升高(P<0.05);β3-AR和eNOS表达逐渐增加(P<0.05)。结论大鼠心力衰竭发展过程中β3-AR和eNOS表达显著增加,这可能为临床治疗心肌肥大和心力衰竭提供新的药物作用靶点。

Objective To detect the expressions of β3-adrenergic receptor（β3-AR） and endothelial nitric oxide synthase（eNOS） from cardiac hypertrophy to heart failure,to provide new ideas for clinical treatment of heart failure.Methods Eighty adult male Wistar rats were randomly divided into two groups： control group（n=10）,model group（n=70）.Heart failure was induced by subcutaneous injections of homologous isoprenaline hydrochloride（170 mg·kg-1·d-1） on 4 consecutive days.Survival rats were randomly divided into myocardial hypertrophy 1 week group,myocardial hypertrophy 2 week group,myocardial hypertrophy 3 week group,myocardial hypertrophy 4 week group and heart failure group.To determine whether the models were successful,all the survival rats were examined by echocardiography separately on 1 week,2 week,3 week,4 week and 6 week.The myocardial ultrastructural changes were observed by transmission electron microscopy.The apoptotic rates of myocardial cells were detected by TUNEL,and expressions of β3-AR and eNOS were analyzed by Western blot.Results Compared with control group,the left ventricular ejection fraction of heart failure group was reduced significantly（P0.01）,left ventricular posterior wall dimensions increased obviously after the injection of isoprenaline hydrochloride for one week,the tendency lasted till the third week,then decreased to the normal level.The apoptosis rate of the myocardial cell increased gradually（P0.05）.The quantitative expressions of β3-AR and eNOS were significantly higher than those in control group.Conclusion The expressions of β3-AR and eNOS increase significantly in the process of the development of heart failure,which may provide a new drug target for the clinical treatment of myocardial hypertrophy and heart failure.