Sato F, Isoyama S, Takishima T
First Department of Internal Medicine, Tohoku University School of Medicine, Sendai, Japan.
Int J Cardiol. 1992 Nov;37(2):131-43. doi: 10.1016/0167-5273(92)90200-m.
The aim of this study was to determine the effects of duration of pressure overload on the reversibility of impaired coronary autoregulation in hypertropied hearts. The experiments were performed on 38 anesthetized male Wistar rats aged 6 to 8 weeks. The ascending aorta was banded for 4 or 10 weeks, then in some rats the bands were removed for 4 weeks. We estimated coronary hemodynamics in a model consisting of isolated non-working hearts perfused with Tyrode's solution containing bovine red blood cells and serum albumin. Myocardial mass increased significantly in 4 and 10-week banded groups compared to controls. Four weeks after debanding in 4- and 10-week banded groups, the value returned to that of controls. Autoregulation gain was significantly lower in banded groups than in controls in the range between 50 and 100 mmHg of coronary perfusion pressure. Although the gain normalized in the debanded group after 4 weeks of banding, the value in the debanded groups after 10 weeks of banding remained less than zero between 25 and 150 mmHg of perfusion pressure. In transient flow response to a stepwise increase of perfusion pressure within the autoregulatory range, promptly increased flow was followed by more rapid and greater decrease in controls than in banded groups. The flow response regressed in the debanded group after 4 weeks of banding, while it remained unchanged in the debanded group after 10 weeks of banding. Thus, duration of pressure overload alters the regression of impaired coronary autoregulation in cardiac hypertrophy.
本研究的目的是确定压力超负荷持续时间对肥厚心脏中受损冠状动脉自动调节可逆性的影响。实验在38只6至8周龄的麻醉雄性Wistar大鼠身上进行。升主动脉结扎4周或10周，然后在一些大鼠中去除结扎带4周。我们在一个由灌注含牛红细胞和血清白蛋白的台氏液的离体非工作心脏组成的模型中评估冠状动脉血流动力学。与对照组相比，4周和10周结扎组的心肌质量显著增加。在4周和10周结扎组解除结扎4周后，该值恢复到对照组水平。在冠状动脉灌注压50至100 mmHg范围内，结扎组的自动调节增益显著低于对照组。虽然在结扎4周后解除结扎组的增益恢复正常，但在结扎10周后解除结扎组，在灌注压25至150 mmHg之间，该值仍小于零。在自动调节范围内对灌注压逐步升高的瞬态血流反应中，与结扎组相比，对照组中迅速增加的血流之后是更快、更大幅度的下降。在结扎4周后解除结扎组中，血流反应恢复，而在结扎10周后解除结扎组中，血流反应保持不变。因此，压力超负荷的持续时间改变了心脏肥大中受损冠状动脉自动调节的恢复。
