OBJECTIVE：To obs erve the protective effect of protoca techuic aldehyde（PAL）on neurovascular unit （NVU） homeostasis damage in rats after cerebral ischemia-reperfusion injury （CIRI）. METHODS ：SD rats were randomly divided into sham operation group ，model group ，PAL high-dose and low-dose groups （10，20 mg/kg），with 11 rats in each group. Administration groups were given relevant medicine intragastrically. Sham operation group and model group were given the same volume of normal saline intragastrically ，10 mL/kg once a day ，for 5 days. After last administration ，CIRI model was induced by suture method ；the ultrastructural changes of NVU were observed by transmission electron microscope. Western blot assay was used to detect the expression of NUV related proteins （MAP-2，GFAP，AQP-4）in cerebral tissue. Immunofluorescence staining was used to observe the positive expression of above proteins in cerebral cortex. RESULTS ：Compared with sham operation group ， blood-brain barrier （BBB）structure of model group was destroyed severely ，the vascular lumen became narrower ，lateral edema of endothelial cells was severe ，and the thickness of basement membrane varied ；the nuclei of neurons were pyknosis and there was a large area of edema in the surrounding tissues ；the structure of glial cells was seriously damaged ，the cell body was shrunk and organelles were lost ；protein expression （or positive expression ）of MAP- 2 in brain tissue （or cerebral cortex ）were significantly decreased （P＜0.05 or P＜0.01），while protein expression （or positive expression ） of GFAP and AQP- 4 were increased significantly（P＜0.01）. After PAL intervention ，the rats had less BBB damage ，and the morphology of vascular lumen and basement membrane were not completely destroyed ；the damage of neurons was alleviated ，the pyknosis of neurons was decreased ， the chromatin was homogeneous and the heterochromatin was decreased；the damage of glial cell structure was alleviated protein expression of GFAP and AQP- 4（except for low-dose group） in cerebral tissue and positive expression of MAP- 2 and GFAP protein in cerebral cortex were reversed @qq.com significantly （P＜0.05 or P＜0.01）. CONCLUSIONS ：PAL can protect the stability of NVU from damage in CIRI model rats； the mechanism may be related to up-regulating the expression of MAP- 2 protein in cerebral cortex and down-regulating the expression of GFAP and AQP- 4 protein in brain tissue.