Objective:To investigate the protective effect of electroacupuncture(EA)on ischemic cerebral neurons and the related intracellular signal transduction mechanism in rats with cerebral ischemia-reperfusion(CI-R).Methods:A total of 24 SD rats were randomized into sham-operation(n=6)

model(n=6)

EA(n=6)and EA+PD 98059(n=6)groups.CI-R model was established by right middle cerebral artery occlusion(MCAO)for 2 hours and reperfusion for 24 hours.EA(disperse and dense waves

80-100 Hz

1-3 mA)was applied to "Dazhui"(GV 14)and "Baihui"(GV 20)for 60 minutes.The activity of extracellular signal-regulated kinases(ERK)positive cells in cerebral cortex tissue was detected with immunohistochemical method.Lumbar intrathecal injection of PD 98059

the inhibitor of mitogen activated protein kinase(MAPK)1(MEK1

2.78 mg/kg)

was conducted in rats of EA+PD 98059 group during CI-R.Results:In comparison with sham-operation group

the score of behavior test and the number of ERK immuno-reaction(IR)-positive neurons of model group decreased significantly(P<0.01

0.05)

while compared with model group

the score and the number of ERK IR-positive neurons in EA group increased markedly(P<0.01).No significant difference was found between model group and EA+PD 98059 group in behavior score and the number of ERK IR-positive neurons(P>0.05).Compared with sham-operation group

the mean area density and mean numerical density of ERK IR-positive neurons in model group were significantly lower(P<0.05)

while in comparison with model group

the mean area density and mean numerical density in EA group were significantly higher(P<0.01);no significant differences were found between model and EA+PD 98059 groups in the area density and numerical density(P>0.05).Conclusion:EA can reduce CI-R induced injury of cerebral neurons

which may be related to its effect in regulating ERK signaling pathway.