压力容积导管系统评价卒中易感性自发性高血压大鼠左心室功能的意义

Assessment of Left Ventricular Function in Stroke-Prone Spontaneously Hypertensive Rats by Pressure-Volume Conductance Catheter System

目的采用压力容积导管研究慢性压力超负荷对高血压大鼠左心室(LV)血流动力学的影响。方法10只6月龄雄性卒中易感性自发性高血压大鼠(SHR-SPs)和10只同月龄雄性 Wistar-Kyoto(WKY)大鼠分别作为高血压组和对照组。对两组大鼠行在体 LV 血流动力学检测,大鼠麻醉后经右颈总动脉向 LV 内插入2F Millar 压力容积导管(SPR-838),记录大鼠稳定状态和改变心脏前负荷时的压力-容积(P-V)变化。结果与 WKY 大鼠比较,SHR-SPs LV 收缩末压、LV 收缩末容积和室内压最大上升速率(+dP/dt_(max))均增高,而射血分数、每搏输出量和心排血量均出现降低(P<0.05)。在压力负荷的影响下,SHR-SPs LV 收缩末压力容积曲线的斜率代偿性增高(P<0.05)。SHR-SPs LV 舒张末压、LV 舒张末容积和 LV 压力衰退的时间常数均高于 WKY 大鼠(P<0.05),而室内压最大下降速率(-dP/dt_(min))低于 WKY 大鼠(P<0.05)。与 WKY 大鼠比较,SHR-SPs 在体 LV P-V 曲线出现了明显的右移。结论 SHR-SPs 发生了 LV 舒张功能障碍及收缩功能减低,并在此基础上伴有一定程度的 LV 扩张。压力容积导管能够客观准确地评价大鼠的心功能。

Objective Using pressure-volume conductance catheter system to investigate the effect of chronic pressure-overload on left ventricular （LV） hemodynamics in hypertensive rats. Methods Six-month-old male stroke-prone spontaneously hypertensive rats （SHR-SPs, n= 10） and age-matched male Wistar-Kyoto （WKY） rats （n=10） were used. The animals were anaesthetized and a 2F Millar pressure-volume conductance catheter （SPR- 838） was inserted through right carotid artery into LV to measure pressure-volume （P-V） relationship. Results We found that left ventricular end-systolic pressure, left ventricular end-systolic volume and ＋dP/dtmax were all remarkablely higher in SHR-SPs than those in WKY rats （P〈0.05）. Compared with WKY rats, ejection fraction, stroke volume and cardiac output were decreased in SHR-SPs （ P〈0.05）. The slope of left ventricular end systolic pressure-volume relationship was greatly elevated in SHR-SPs. The constant of isovolumeric relaxation （Tau） was prolonged in SHR-SPs （P〈0.05） and left ventricular end-diastolic pressure and left ventricular end-diastolic volume were significantly increased in SHR-SPs than in WKY rats （P〈0.05）. In addition, -dP/dtmin. was decreased in SHR-SPs （P〈0.05）. The in vivo P-V loop curve was notably rightward shifted in SHR-SPs. Conclusion These results show that pressure-overload could induce LV diastolic dysfunction, deterioration of systolic performance and partial LV dilation. The pressure-volume conductance catheter system is an useful tool for objective and accurate assessment of cardiac function in rats.