Objective: To explore the mechanism of electroacupuncture (EA) underlying improvement of cerebral infarction (CI) by investigating its influence on expression of cerebral Wnt7a, lymphoid enhancer factor-1 (LEF1), glycogen synthase kinase 3β(GSK-3β) and Dickkopf-1(DKK1) mRNA and proteins in CI rats.
Methods: A total of 280 male Wistar rats were randomly divided into blank control (n＝10), sham-operation, model and EA groups，and 90 rats of the last 3 groups were further divided into 1, 3, 6, 9, 12 and 24 h, and 3, 7 and 12 d subgroups with 10 rats in each subgroup. The CI model was established by occlusion of the middle cerebral artery (MCAO). The sham-operation group received the same surgical operation but without thread embolus insertion. EA (2 Hz/15 Hz, 2 mA) was applied to "Shuigou" (GV26) for 20 min, once a day for 1, 3, 7 and 12 d, respectively. The neurological deficit was evaluated by using Neurological Severity Scores (NSS). The expression levels of Wnt7a，LEF1, GSK-3β and DKK1 mRNAs and proteins in the right ischemic brain tissues were detected by Quantative real-time PCR and Western blot, respectively.
Results: After MCAO, the NSS score was significantly increased in the model and EA groups relevant to the blank control and sham-operation groups (P<0.01) and gradually decreased with the prolongation of ischemia time. After EA, the NSS scores were notably decreased on day 3, 7 and 12 in the EA group compared with the model group (P<0.05, P<0.01). After modeling, the expression levels of Wnt7a and LEF1 mRNAs from 3 h to 12 d, Wnt7a and LEF1 proteins from 6 h to 12 d were considerably increased (P<0.01, P<0.05), while those of GSK-3β mRNA at 9, 12 and 24 h, GSK-3β protein at 24 h and 3 d, and DKK1 mRNA at 24 h and 3 d and DKK1 protein at 3 d were obviously decreased in the model group relevant to the sham-operation group (P<0.05, P<0.01). After the intervention, the expression levels of Wnt7a mRNA at 12 h to 3 d, Wnt7α protein from 24 h to 12 d, LEF1 mRNA from 24 h to 12 d, and LEF1 protein from 3 d to 12 d were further apparently up-regulated (P<0.01, P<0.05), while those of GSK-3β mRNA at 9 h, 3，7 and 12 d, and GSK-3β protein at 12 h, 7 d and 12 d, and DKK1 mRNA at 12 h, 24 h and 3 d, and DKK1 protein at 24 h to 12 d were obviously down-regulated in the EA group relevant to the model group (P<0.01, P<0.05). No significant difference was found between the blank and sham-operation groups in the NSS scores and expression levels of Wnt7a, LEF1, GSK-3β and DKK1 mRNAs and proteins at all the time points (P>0.05).
Conclusion: EA of GV26 can significantly improve the neurological deficit symptoms in MCAO rats, which may be associated with its effects in up-regulating the expression of Wnt7a and LEF1 mRNAs and proteins, and in down-regulating the expression of GSK-3β and DKK1 mRNAs and proteins.
Keywords: Cerebral infarction; Electroacupuncture; Neurological function; Shuigou (GV26); Wnt signaling pathwaya.