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目的:观察压力负荷型心肌肥大大鼠左室射血功能及其神经肽Y(NPY)受体亚型(Y_1、Y_2、Y_4和Y_5)的表达变化。方法:腹主动脉缩窄法建立大鼠压力过负荷心肌肥大模型,测量全心和左心室的重量;颈总动脉插管检测左心室血流动力学;IE33彩超仪测量左室壁厚度、内径、容积,以及左室射血功能相关指标;荧光定量PCR法检测左心室组织匀浆中NPY各受体亚型mRNA的表达。结果:与假手术组相比,腹主动脉缩窄大鼠全心/体重、左室/右室均明显增高(P<0.05),左室内压力峰值(LVSP)、左室等容收缩末期压力上升最大速率(+dsp/dt_(max))和左室舒张期压力下降最大速率(-ddp/dt_(max))明显增高(P<0.05)。M型超声心动图显示,腹主动脉缩窄大鼠舒张末期室间隔厚度(IVSd)、收缩末期室间隔厚度(IVSs)、舒张末期左室后壁厚度(LVPWd)以及收缩末期左室后壁厚度(LVPWs)也较假手术组显著增加(P<0.05);通过超声推算出的左室质量,与实际测得的数值高度相关(r=0.997,P<0.05);心输出量(CO)下降至假手术组的55%(P<0.01)。另外,与假手术组相比,压力负荷型肥大心肌Y_1、Y_2、Y_4和Y_5受体的表达均显著减少(P<0.05)。结论:压力负荷导致左心室明显肥厚,收缩和舒张功能增强但心输出量降低;肥厚心肌中NPY受体各亚型表达量均显著降低。
Objective: To observe the changes of left ventricular ejection function and the expression of neuropeptide Y (NPY) receptor subtypes (Y_1, Y_2, Y_4 and Y_5) in rats with pressure overload. Methods: The model of myocardial hypertrophy induced by pressure overload in rats was established by abdominal aorta constriction. Left ventricular hemodynamics was measured by carotid artery cannulation. Left ventricular wall thickness and diameter , Volume, and left ventricular ejection fraction; fluorescence quantitative PCR was used to detect the mRNA expression of NPY receptor subtypes in left ventricular tissue homogenate. Results: Compared with the sham-operation group, the total heart / body weight, left ventricle and right ventricle were significantly increased (P <0.05), left ventricular pressure peak (LVSP), left ventricular end-systolic pressure The maximum rate of increase (+ dsp / dt max) and the maximum rate of left ventricular diastolic pressure (-d dp / dt max) were significantly increased (P <0.05). M-mode echocardiography showed that the changes of end-diastolic ventricular septal thickness (IVSd), end-systolic septal thickness (IVSs), end-diastolic left ventricular posterior wall thickness (LVPWd) and left ventricular posterior wall thickness (LVPWs) were significantly higher than those in the sham operation group (P <0.05). The left ventricular mass estimated by ultrasound was highly correlated with the actual measured values (r = 0.997, P <0.05) To 55% of the sham-operated group (P <0.01). In addition, the expression of Y_1, Y_2, Y_4 and Y_5 receptors was significantly decreased in stress-loaded hypertrophic myocardium compared with sham operation group (P <0.05). Conclusion: The left ventricular hypertrophy is induced by pressure overload, and the systolic and diastolic functions are enhanced but the cardiac output is decreased. The expression of NPY receptor subtypes in hypertrophic myocardium is significantly reduced.