Department of Neurology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
J Neurosci Res. 2011 Jan;89(1):108-16. doi: 10.1002/jnr.22522.
Chronic mild hypoperfusion has been shown to enlarge pial collateral vessels in normal mouse brains. The purpose of this study was to clarify the effect of hypertension on pial collateral vessel development after chronic hypoperfusion using spontaneously hypertensive rats (SHR). In normotensive rats, unilateral common carotid artery (CCA) occlusion enlarged leptomeningeal collateral vessels. CCA occlusion also preserved residual cerebral blood flow (CBF) and attenuated infarct size after middle cerebral artery (MCA) occlusion 14 days later. In contrast, in SHR, CCA occlusion neither enlarged the leptomeningeal anastomosis nor showed protective effects after MCA occlusion. However, decreasing blood pressure using an angiotensin II AT1 receptor blocker restored the beneficial effect of CCA occlusion on collateral growth as well as on residual CBF and infarct size after MCA occlusion. Adaptive responses in CBF autoregulation curves observed 14 days after CCA occlusion in normotensive rats were impaired in untreated SHR, but were restored after antihypertensive treatment. In conclusion, SHR have impaired leptomeningeal collateral growth after CCA occlusion, but antihypertensive treatment restores the beneficial effect of CCA occlusion on collateral circulation.
慢性轻度低灌注已被证明可使正常小鼠大脑的脑膜侧支血管扩张。本研究旨在阐明高血压对慢性低灌注后脑膜侧支血管发育的影响，使用自发性高血压大鼠（SHR）作为研究对象。在正常血压大鼠中，单侧颈总动脉（CCA）闭塞可使脑膜侧支血管扩张。CCA 闭塞还可保留残余脑血流（CBF），并减轻 14 天后大脑中动脉（MCA）闭塞引起的梗死面积。相比之下，在 SHR 中，CCA 闭塞既没有扩大脑膜吻合，也没有在 MCA 闭塞后表现出保护作用。然而，使用血管紧张素 II AT1 受体阻滞剂降低血压可以恢复 CCA 闭塞对侧支生长以及 MCA 闭塞后残余 CBF 和梗死面积的有益作用。在 CCA 闭塞后 14 天观察到的正常血压大鼠 CBF 自动调节曲线的适应性反应在未经治疗的 SHR 中受损，但在降压治疗后得到恢复。总之，SHR 在 CCA 闭塞后脑膜侧支生长受损，但降压治疗可恢复 CCA 闭塞对侧支循环的有益作用。
