Objective:To study the effect of electroacupuncture(EA)on changes of aquaporin-4(AQP4)expression in rats with cerebral ischemia/reperfusion(CI/R).Methods:One hundred and seventy male Sprauge-Dawley rats were randomized into control(n=50)

CI/R model(n=60)and EA(n=60)groups

and the later 2 groups were further divided into 6 h

12 h

24 h

48 h and 72 h subgroups

with 12 cases in each.CI/R model was established by occlusion of the middle cerebral artery(MCAO).EA(3.85/6.25 Hz

0.8-1.0 mA)was applied to “Shuigou”(GV 26)and “Baihui”(GV 20)for 30 min.Transcardial perfusion was conducted with normal saline+paraformaldehyde in rats of different groups for taking brain tissue samples.The degree of brain edema was detected by cresyl violet stain method

permeability of the blood-brain barrier(BBB)reflected with IgG value in brain tissue was displayed by immunohistochemistry

and AQP4 protein and mRNA expression of corpora striata(CS)were detected by using immunohistochemistry(ABC)and RT-PCR techniques respectively.Results:Twelve hours after CI/R

the hemisphere of brain began to get swelling significantly and the exosmose state of IgG became evidently;compared with the corresponding phases of model group

the swell rates in 24 h

48 h and 72 h subgroups of EA group were significantly lower(P<0.05

0.01)

and nearly no IgG immunoreaction positive products were found in different phases of EA group.The expres-sion of AQP4 protein and mRNA increased significantly from 12 h and 24 h on separately in model group

while the expression in EA group was markedly weaker.The ratios of AQP4 mRNA and β-actin mRNA of CS on the affected side of the brain from 24 h to 72 h of EA group were significantly lower than those of model group(P<0.05

0.01).Conclusion:EA can reduce the degree of brain edema induced by CI/R and improve the degree of!BBB injury

which may be related to its effect in down-regulating AQP4 expression.