Electroacupuncture alleviates nerve injury after cerebra ischemia in rats through inhibiting cell apoptosis and changing the balance of MMP-9/TIMP-1 expression

Accumulating evidence demonstrates that acupuncture and electroacupuncture (EA) can exert a neuroprotective role for cerebral ischemia, but their precise mechanism remains largely unknown. Therefore, in this study, the effects of EA stimulation on cerebral ischemia reperfusion and its neuroprotective mechanisms were investigated. A rat model of middle cerebral artery occlusion (MCAO) was developed, and EA stimulation (2 Hz, 1 mA) at Baihui and Siguan acupoints was applied 30 min after MCAO and then once daily for 7 consecutive days. The results indicated that EA stimulation significantly reduced the cerebral infarct area and neurological deficit scores, decreased the number of apoptotic cells, up-regulated Bcl-2 protein expression, and down-regulated Bax protein expression. EA stimulation resulted in a significant increase of proliferative cells in the cerebral tissues. Additionally, EA stimulation significantly down-regulated the expression levels of matrix metalloproteinase -9 (MMP-9) mRNA and protein, and simultaneously up-regulated the expression levels of tissue inhibitor of metalloproteinases-1 (TIMP-1) mRNA and protein, which resulted in an imbalance of MMP-9/TIMP-1expression, although it did not significantly change MMP-2 and TIMP-2 expression. These findings indicate that EA stimulation at Baihui and Siguan acupoints exerts a neuroprotective role against cerebral ischemia-reperfusion injury, which is probably associated with the inhibition of apoptosis and altering the balance of MMP-9/TIMP-1 expression.