高血压大鼠脑血管功能损害的临界关闭压评价

A functional evaluation of hypertensive cerebrovascular lesions by critical closing pressure

目的通过临界关闭压(CCP)动态观察高血压脑微动脉平滑肌的收缩程度与形态改变间的关系。方法对照组和高血压组大鼠各80只,在高血压形成术后的不同时间点,分别测定脑血管CCP、脑血流自动调节下限(LLCA)和脑血管形态变化。结果高血压组大鼠的CCP逐渐升高,到14、16周明显高于对照组(P<0.05)。CCP的升高与平均动脉压、微动脉中膜厚度及LLCA呈正相关(P<0.05),并且在血压升高初期和血压较高后变化明显,呈倒“S”形改变(P<0.05)。结论高血压大鼠脑微动脉平滑肌的收缩程度明显增强,是微动脉中膜增厚的功能表现,并且在血压升高初期和血压较高后改变比较明显。

Objective To dynamically observe the degree of cerebral arteriolar smooth muscle contraction and the relation between it and morphological changes by critical closing pressure （CCP）. Methods There were 80 rats each in control and hypertension groups. The CCP, lower limit of cerebral autoregulation （LLCA） and the arteriolar morphology of the rats were determined at different time points after operation. Results The CCP of hypertensive rots rose step by step after operation, and was significantly higher than that of control at 14th and 16th weeks （ P 〈 0.05）. The shifting of CCP was positively correlative to mean arterial blood pressure, thickness of tunica media of cerebral arterioles and LLCA （ P 〈 0.05）. The elevation of CCP was evident at early stage of increase in blood pressure and after significant increase in blood pressure, showing a reverse S pattem（ P 〈 0.05）. Conclusion Cerebral arteriolar smooth muscle contracts markedly in hypertensive rats, and the degree of contraction correlate to thickness of tunica media of cerebral arterioles, which changes obviously at early period of hypertension and after significant increase in blood pressure.