心内膜对大鼠肥厚心肌力学的影响(英文)

目的:观察心内膜对大鼠肥厚心肌力学的影响.方法:采用两肾一夹肾性高血压大鼠离体乳头肌标本,化学去内膜法. 结果:肾血管性高血压大鼠肥厚乳头状肌等长收缩静息张力、发展张力与假手术组相似,±dT/dt_(max)降低, dT/dt_(max)及—dT/dt_(max)时程、收缩峰值时间及半数舒张时间延长.去除心内膜心肌标本收缩峰值时间及半数舒张时间显著缩短,—d7/dt_(max)显著升高而 dTdt_(max)无改变,因而两者比值显著下降. 结论:心内膜主要影响心肌舒张反应及舒张早期充盈,在心肌肥厚代偿机制中起到一定作用.

Effects of endocardial endothelium in myocardial mechanics of hypertrophied myocardium of rats

To investigate the effects of endocardial endothelium (EE) in myocardial mechanics of hypertrophied myocardium of rats. METHODS: Hypertrophied myocardium has been developed through long-term renovascu-lar hypertension in rats. Selective stripping of EE was achieved chemically and the effects of EE on the activation and relaxation of hypertrophied myocardium were investigated and compared to those in the presence and absence of intact EE. RESULTS: Resting tension (RT) and peak developed tension (DT) of isometric contraction of the left ventricular papillary muscles of renovascular hypertensive rats (RHR) remained similar, but maximal rate of tension development and fall ( dT/dtmax and- dT/dtmax) were lowered, time to dT/dtmax (TPP) and time to -dT/dtmax(TPN) were increased , and time to peak developed tension (TPT) and half relaxation time (RTl) were prolonged, vs sham-operated rats (Sham). After EE denudation, TPT, and RTl were significantly abbreviated in RHR. The- dT/dtmax was significantly augmented while the dT/dtmax was unaltered, resulting in a prominent decrease in the ratio of dT/dtmax to -dT/dtmax.CONCLUSION: EE predominantly influences the relaxation in isolated myocardium and early diastolic filling events in hearts, and is involved in the cardiac compensatory mechanism in hypertrophied myocardium.