大鼠静脉窦高压后硬脑膜微循环变化的动态观察

目的观察大鼠静脉窦高压后硬脑膜微循环的变化，探讨硬脑膜动静脉瘘发生的机制。方法将110只大鼠随机分成两组：实验组85只，对照组25只。实验组大鼠闭塞其上矢状窦和左侧横窦，同时行右侧颈总动脉和颈外静脉吻合，造成静脉窦高压。然后分别在术后7、14、21、28、40、60、90d取实验组大鼠3只和对照组大鼠1只观察硬脑膜微循环，并计量上矢状窦旁开1mm，分别与上矢状窦平行和垂直的1mm直线上所能观察到的直径≤10μm的血管数目和直径的变化。结果在静脉窦高压7d，大鼠硬脑膜未见血管增生；14d后硬脑膜才出现血管增生。90d后，实验组和对照组血管数目差异无显著性（P〉0．05）。实验组大鼠硬脑膜中可观察到毛细血管网中动静脉直接通道的开放，血液经该通道进入静脉的路径直而短（21d）。第28天时实验组大鼠可观察到动静脉瘘形成，而且其形态和结构与正常动静脉短路类似，但连接的血管增粗，不再是毛细血管。结论静脉窦高压形成初期，硬脑膜血管增生活跃，后期血管增生减弱或消失。从瘘口的位置和结构分析，瘘口很可能是由原来存在的血管薄弱部位逐渐演化而来。

The changes of dural microcirculation after venous sinus hypertension in rats: a dynamic observation

Objective To investigate the mechanisms of dural arteriovenous fistula(DAVF) by observing the changes of dural microcirculation after venous sinus hypertension in rats.Methods One hundred ten rats were randomly allocated into experimental(n=85) and control groups(n=25).Superior sagittal sinus and left transverse sinus were occluded in the experimental group.At the same time,the right common carotid artery and external jugular vein anastomosis were performed,and venous sinus hypertension was induced.Then the dural microcirculation of 3 rats in the experimental group and 1 in the control group was evaluated on day 7,14,21,28,40,60,and 90 respectively after the procedure,and the changes of vascular numbers and diameters at the levels of superior sagittal sinus 1 mm aside and 1 mm in the vertical direction that could be cut were evaluated.Results The dura mater did not show angiogenesis in the early dural venous sinus hypertension(7 days) in rats,and only after the dural venous sinus hypertension had existed for a period of time(14 days) that the angiogenesis would appear.There were no significant differences between the two groups on the numbers of blood vessels 90 days after venous sinus hypertension (P>0.05).The opening of arteriovenous direct passages in the capillary network could be observed in the experimental group;and the passages that blood passed through were direct and short(21 days).The formation of DAVF was observed on day 28 in the experimental group,and its morphology and structure was similar to that of the normal arteriovenous shunt.The only difference was that the linked blood vessels become thick and they no longer to be capillaries.Conclusion In the initial stage of venous sinus hypertension,the angiogenesis was active,but it was attenuated and disappeared in late the stage.The analysis from the position and structure of fistula opening showed that it was likely that it was gradually evolved from the original weak position of blood vessel.