Aim of the study:To evaluate the effects of TQHXD on the Blood-Brain Barrier (BBB) permeability and the expressions of related proteins on the rats and analyse the constituents in the cerebrospinal fluid on the rats with cerebral ischemia injury.Materials and Methods:Cerebral ischemia rats were induced by middle cerebral artery occlusion (MCAO).Adult male Sprague-Dawley (SD) rats were randomly divided into seven groups:sham-group;model group;Nimodipine (NMP)-treated group;Nao Mai Tai (NMT)-treated group and TQHXD-treated group (3,6 and 12g/kg body weight);The neurological function of rats was estimated by neurological defect scoring after the 1 day,7 days and 15 days after administration.Histological structure of the brain in rats were observed by hematoxylin and eosin (H &E) staining.Ultramicrostructural features of hippocampus neurons and the opening of tight junction (TJ) of BBB in rats were observed by Transmission Electron Microscope (TEM).Westem blot was performed to detect the expression of ZO-l,Occludin,claudin-5,AQP-4 and MMP-9 in BBB after cerebral ischemia injury.Component analysis experiments:Adult male SD rats were randomly divided into four groups:Distilled water was administered intragastrically sham-operated rats (A)and normal rats (B),TQHXD was administered intragatrically sham-operated rats (C);TQHXD was administered intragestrically model rats (D).GC and HPLC was developed for determination of three compounds,namely,Muscone,Ligustilide and Hydroxysafflor yellow A,in cCerebrospinal fluid (CSF) of rats after oral administration of TQHXD.Finally,samples of cerebrospinal fluid (CSF) of rats in each group were compared with each botanical,resulting we determined these three compounds come from which herb.Results:TQHXD significantly reduced the neurological defect scores.Histological examination indicated that dense neuropil and largely surviving neurons were seen in TQHXD-treated rats.Observation of transmission electron microscope revealed that TQHXD could significantly inhibit the damage of hippocampal neurons and reduce the opening of TJ.The decreased protein expression levels of claudin-5,occludin,ZO-l and the increased protein expression levels of AQP-4 and MMP-9 in cerebral ischemia tissue were significantly prevented by treatment of TQHXD.Analysis of experimental results showed that Muscone,Ligustilide and Hydroxysafflor yellow A could penetrate the Blood-brain barrier into the CSF,and the concentration of Muscone,Ligustilide and Hydroxysafflor yellow A in CSF of the normal groups was higher than that in CSF of the model group.Conclusion:These results demonstrated that TQHXD may act as a potential neuroprotective agent against BBB damage for cerebral ischemia through protectcting the protection of hippocampus neurons,reducing the reduction the opening of TJ and decreasing decrease the permeability of BBB by up-regulating the expressions of ZO-1,Occludin,Claudin-5,down-regulating AQP-4 and MMP-9 expressions.Beside,Muscone,Ligustilide and Hydroxysafflor yellow A might be the therapeutic material basis of TQHXD.