Objective To observe the impact of preconditioning of EA stimulation of"Baihui"(GV 20)and"Shuigou"(GV 26)in different duration on expression of matrix metalloproteinase(MMP)-9and vascular endothelial growth factor(VEGF)in blood-brain barrier(BBB)tissues in rats with cerebral ischemia-reperfusion injury(CI/RI).Methods Sixty-four male SD rats were randomly allocated to sham-operation(sham)

model

EA-pretreatment 7days(pre-t-7d)and EA-pre-t-15dgroups(16rats/group

8rats for immunohistochemistry and 8for RT-PCR).The CI/RI model was established by occlusion of the middle cerebral artery for 90 min and reperfusion.EA(2Hz/15 Hz

1mA)was applied to GV 20 and GV 26 for 30min

once daily for 7days and 15 days respectively before modeling.Immunohistochemical staining and fluorescence quantitative RT-PCR were employed to detect the expression of MMP-9protein

MMP-9mRNA and VEGF mRNA in the BBB tissues(choroid plexus).Results Compared with the sham group

the number of MMP-9immuno-reaction positive cells

and the expression of MMP-9mRNA and VEGF mRNA in the model group were significantly increased(P<0.001)

while compared with the model group

the number of MMP-9positive cells

and expression levels of MMP-9mRNA and VEGF mRNA in the EA-pre-t-7dand EA-pre-t-15 dgroups were significantly reduced(P<0.01)

and the effects of EA-pre-t-15 dwere markedly superior to those of EA-pre-t-7d(P<0.01

P<0.05).Conclusion EA-pretreatment of GV 20 and GV 26 can effectively restrain CI/RI-induced increase of expression of MMP-9protein

MMP-9mRNA and VEGF mRNA in blood-brain barrier in CI/RI rats

which may contribute to its protective effect of ischemic cerebral tissue.Longer EA-pretreatment is relatively better.