RESUMEN
OBJECTIVE: To study the underlying mechanism of electroacupuncture (EA) in improving learning-memory ability in vascular dementia (VD) rats. METHODS: SD rats were randomized into control, sham operation (sham), VD model, non-acupoint and acupoint groups, with 10 cases in each. VD model was established by occlusion of the bilateral common carotid arteries. Morris water maze test was performed to detect the rats' learning-memory ability. The expression of N-methyl-D-aspartate receptor (NMDAR)-2 B mRNA in hippocampal CA 1 region and dentate gyrus was measured by hybridization in situ. EA (2 Hz, 1-2 mA)was applied to "Baihui" (GV 20), "Dazhui" (GV 14) and bilateral "Shenshu"(BL 23) and non-acupoint (the chest-abdominal juncture between the first and the second lumbar vertebrae) for 20 min, once daily for 30 days. RESULTS: Self-comparison showed that 6 weeks after modeling, the escape latencies of control and sham groups, and the lingering duration in the 3rd quadrant of water pool of model, non-acupoint and acupoint groups decreased significantly (P < 0.05), while the escape latencies of model, non-acupoint and acupoint groups, and the lingering duration of control and sham groups increased considerably (P < 0.5). No significant differences were found between control and sham groups, and among model, non-acupoint and acupoint groups in the escape latency and the lingering duration in the 3rd quadrant (P > 0.05). On the 11th week after modeling, compared to their individual escape latencies and lingering duration on the 6th week, the escape latencies of controll sham and acupoint groups shortened obviously (P < 0.05), while the lingering duration in the 3"rd quadrant of the same 3 groups postponed significantly (P < 0.05). Compared with model group, the escape latency of acupoint group shortened obviously and the lingering duration increased significantly (P < 0.05). No significant differences were found between control and sham groups, and between model and non-acupoint groups in these two indexes (P > 0.05). Compared to control/sham group, the grey values of NMDAR-2 BmRNA expression in hippocampal CA 1 region and dentate gyrus in model and non-acupoint groups decreased significantly (P < 0.05). Compared to model group, the grey values of NMDAR-2 B mRNA expression in these two brain regions increased markedly (P < 0.05). No significant difference was found between control and sham groups, and between model and non-acupoint groups (P > 0.05). CONCLUSION: Acupoint-EA is able to improve VD rats' learning-memory ability which may be related to its effect in upregulating the expression of NMDAR-2 B mRNA in hippocampal and dentate gyrus.