临界关闭压对高血压大鼠脑血流的调控作用

Role of Critical Closing Pressure on Cerebral Blood Regulation on Rats

目的探讨临界关闭压(Critical closing pressure,CCP)对肾血管性高血压大鼠(renovascularhypertensive rats,RHR)脑血流动力学改变的调控作用。方法 RHR模型(RHR组)26只,假手术正常血压对照组24只,同步记录大脑中动脉血流速度(cerebralblood flow velocity,CBFV)和有创血压,按照CCP理论计算CCP和小动脉阻力,并分析血流动力学参数之间,以及血流动力学参数与血管形态参数改变间的关系。结果与对照组比较,RHR组动脉血压明显升高的同时,脑循环有效灌注压(effective cerebralperfusion pressure,CPPe)和血管面积阻力指数(resistance area product,RAP)明显升高(CPPe:100.80±26.40mmHg vs 67.30±13.10mmHg,P<0.01;RAP:2.94+0.85 vs 2.30±0.59,P=0.003),但CBFV相对稳定,脑循环阻力(cerebral vascular resistance,CVR)升高不明显。RHR组血管面积阻力指数(resistancearea product,RAP)只与小动脉管腔内径呈负相关(r_s=-0.610,P=0.001),CCP与小动脉中膜厚度呈正相关(r_s=0.554,P=0.006);而CVR不仅与小动脉管腔内径呈负相关(r_s=-0.463,P=0.023),也与小动脉中膜厚度呈正相关(r_s=0.678,P<0.01)。结论 RHR的脑血流调控可通过CCP和RAP的改变来完成,用CCP和RAP代替CVR,能更加真实、客观地反映脑血流动力学的调控机制。

Objective To validate the role of the model of critical closing pressure（CCP） on cerebral blood regulation. Methods After renovascular hypertensive rats（RHR） were made, the cerebral blood flow velocity（CBFV） and artery blood pressure were monitored simultaneously. The values of CCP and arteriolar resistance were worked out according to CCP theory. The difference of indexes between RHR and control were compared. The relationship between hemodynamics parameters and the association between hemodynamics and arteriolar morphological indexes were evaluated. Results The effective cerebral perfusion pressure（CPPe） and resistance-area product（RAP） in RHR（100.8±26.4 mmHg, 2.94±0.85） increase more following artery blood pressure rising, compared with those in control（67.3±13.1 mmHg, 2.30±0.59）（P〈0.001, P=0.003）, while CBFV is steady and cerebral vascular resistance（CVR） increase slightly. RAP correlates with arteriolar luminal radius negatively（rs=-0.610, P=-0.001 ） and CCP associates with arteriolar media thickness positively（rs=0.554, P=0.006） whilst CVR has both correlations with luminal radius（rs=-0.463, P=0.023） and media thickness（rs=0.678, P=0.000）. Conclusion The cerebral blood regulation on rats can be more effectively evaluated by dynamic adjusting of CCP and RAP comparing with CVR.