| Vagus nerve stimulation (VNS) has been applied to cure difficult-to-treat epilepsy for about 20 years. The technique was also reported to have effects on many other nervous disorders, such as depression, migraine and Alzheimer's disease, improving cognition, locomotion performance of the patients. We predict VNS may produce beneficial effects on another disease, stroke. Electroacupuncture (EA), as a therapeutic method of traditional Chinese medicine, has been used to cure the patients in both acute phase and chronic phase of stroke, and was reported to have good curative effects. In order to observe whether VNS can relief the defect of cognition and locomotion induced by brain ischemia and compare its effects with that of EA , we made animal model of brain ischemia using middle artery occlusion method (MCAO), treated the animal with EA or VNS and then deployed behavioral test, including Morris water maze, passive avoidance test,active avoidance test (automated shuttle-boxes) and rota-rod test to assess learning and memory function and motor skill of the MCAO rats subjected to VNS or EA. The results indicate: in the group of Morris water maze test, on the fifth day after surgery, the difference in time the rats needed to find platform (latency) between sham-MCAO, MCAO, VNS+MCAO and EA+MCAO group was significant (P<0.05). The difference in latency between sham-MCAO group and MCAO group was significant (P<0.05) as well as MCAO group and EA+MCAO group (P<0.05). The latency of MCAO rats was significantly longer than that of sham-MCAO rats. Meanwhile, the difference in latency of EA+MCAO rats and sham-MCAO rats was not significant. But compared with MCAO rats, the rats of EA+MCAO group had a shorter latency. However, the latency between MCAO group and VNS+MCAO group seemed not different. During Morris water maze test, the velocity of rats in four groups was not significantly different. In passive avoidance test, on the fifth day after surgery, the difference between four groups was significant (P<0.01). The rats treated with VNS and MCAO had a longer latency than that subjected to MCAO only (P<0.05). Meanwhile, the rats from MCAO group had a shorter latency than that from EA+MCAO group (P<0.05). On the day 7 after surgery, The MCAO rats had a shorter latency than sham-MCAO rats (P<0.05), VNS+MCAO rats (P<0.05) and EA+MCAO rats (P<0.05). On the fifth day after surgery, the difference in the number of electric shock triggered by rats became significant (P<0.05). Two days later, the difference seemed more remarkable (P<0.01). The number in MCAO group was bigger than that in sham-MCAO group (P<0.01), VNS+MCAO group (P<0.01) and EA+MCAO group (P<0.01). In automated shuttle-boxes test, on the day 10 after surgery, the difference in avoidance CR rate between four groups became significant (P<0.05). On the day 13, the difference between MCAO and VNS+MCAO group was significant (P<0.05). The difference between MCAO and EA+MCAO group was also significant (P<0.05). We also analyzed the avoidance latency of the rats in the four groups. On the day 6 (P<0.05) and day 8 (P<0.01) after surgery, the difference in avoidance latency between four groups was significant. The avoidance latency was shorter in EA+MCAO group and VNS+MCAO group than that in MCAO group on day 6 (P<0.05). The sham-MCAO rats as well as EA+MCAO rats had shorter avoidance latency than MCAO rats on day 8 (P<0.01). In Rota-rod test, on day 5 after surgery, the time of rats to stay on the rotating beam decreased sharply, the difference in time of four groups was significant (P<0.05). On the sixth day after surgery, the rats of MCAO group had shorter time on the rod than that of VNS+MCAO rats and EA+MCAO group (P<0.05). It is concluded from the results that EA can improve memory and learning function and motor coordination of the rats subjected to MCAO; while VNS has no remarkable effects on the spacial memory of the MCAO rats, but it enhances the cognition function as well as the motor coordination of MCAO rats. |
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