Abstract：
We investigated the effect of a decrease in blood viscosity on the mean BP during isovolumic hemodilution and vasodilating activity of the endothelium in normotensive Wistar rats and spontaneously hypertensive rats (SHR). Blood viscosity was reduced by isovolumic hemodilution (replacement of 10% of circulating blood with an equal volume of plasma). Hemodilution caused the same reduction in blood viscosity by 16% in both groups of rats. In Wistar rats, a decrease in blood viscosity did not significantly change in the mean BP; no significant correlations between blood viscosity and mean BP were observed before and after hemodilution. In SHR, a decrease in blood viscosity led to a significant decrease in the mean BP by 18%. Correlations were found between the mean BP and blood viscosity in SHR before (r=0.63; p=0.028) and after (r=0.71; p=0.009) isovolumic hemodilution. In SHR, a decrease in the index of vasodilating activity of the endothelium due to a decrease in the vasodilatory response to intravenous administration of the endothelium-dependent vasodilator acetylcholine was revealed. In SHR, BP passively follows the change, in this case, the decrease in blood viscosity, which attests to impaired BP regulation in response to changes in shear stress on the vascular endothelium caused by the development of endothelial dysfunction in hypertensive animals.
摘要：
我们研究了血压正常的Wistar大鼠和自发性高血压大鼠（SHR）在等容血液稀释和内皮血管舒张活性期间血液粘度降低对平均BP的影响。等容血液稀释（用等体积的血浆代替10％的循环血液）降低了血液粘度。血液稀释使两组大鼠的血液粘度降低了16％。在Wistar大鼠中，血液粘度的降低并未显著改变平均BP;血液稀释前后血液粘度与平均BP之间没有显著相关性.在SHR,血液粘度降低导致平均血压显著降低18%.在等容血液稀释之前（r=0.63；p=0.028）和之后（r=0.71；p=0.009），SHR的平均BP与血液粘度之间存在相关性。在SHR,发现由于静脉内施用内皮依赖性血管扩张剂乙酰胆碱的血管舒张反应降低,内皮的血管舒张活性指数降低.在SHR,BP被动地跟随变化，在这种情况下,血液粘度的降低，这证明了血压调节受损，以响应由高血压动物内皮功能障碍的发展引起的血管内皮剪切应力的变化。
