| Blood brain barrier (BBB) disruption and subsequent brain edema are major contributors to the pathogenesis of ischemic stroke, while current clinical therapy remains unsatisfied. Electroacupuncture (EA) pretreatment has the protective effect against cerebral ischemia/reperfusion (I/R). However, the underlying mechanisms have not been fully understood. In this study, we investigated the effect of EA pretreatment on blood brain barrier disruption in a focal cerebral ischemia/reperfusion (I/R) rat model. Male Sprague-Dawley rats (280 to 320 g) were pretreated with EA at the acupoint "Baihui"(GV20) 30min/d, for consecutive 5d before focal cerebral ischemia which was induced for 120 min by middle cerebral artery occlusion (MCAO). The results showed that infarction volume, cerebral apoptosis, brain water content and neurological deficits increased in MCAO model rats 3h, 24h after reperfusion, and were attenuated significantly by EA pretreatment. Furthermore, electron microscopy confirmed the brain edema reduction in EA pretreated rats. Western blot analysis showed that the tight junction proteins between endothelial cells, such as Claudin-5, Occludin, were significantly degradated, but the protein expression of p-Caveolin-1, the principal\marker of caveolae in endothelial cells, and p-Akt increased after ischemia, all of these were alleviated by EA pretreatment. While there were no significant difference in Caveolin and Akt expression. In addition, the expression of eNOS was significantly increased after reperfusion, and alleviated by EA pretreatment. In conclusion, the pretreatment with EA significantly reduced BBB permeability and brain edema, which were correlated with preventing the degradation of the tight junction proteins and inhibiting the expression of p-Caveolin-1 in the endothelial cells. |
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