[Influence of Electroacupuncture Stimulation with Different Intensities and Therapeutic Intervals on Learning-memory Ability and Expression of Aβ 1-40 and Arginine Vasopressin Genes in the Hippocampal CA 1 Region in VD Rats].

Objective: To observe the influence of electroacupuncture (EA) stimulation with different electrical current intensities and therapeutic intervals on learning-memory ability and expression of β-amyloid peptide Aβ 1-40 and arginine vasopressin (AVP) genes in the hippocampal CA 1 region in vascular dementia (VD) rats, so as to provide evidence for treatment of VD.
Methods: A total of 48 male SD rats were randomly divided into sham, model, 0.5 mA-5 d-EA, 1.5 mA-5 d-EA, 0.5 mA-1 d-EA and 1.5 mA-1 d-EA groups ( n =8 in each group). The VD model was established using modified 4-vessels occlusion method. EA (alternative 2 Hz/15 Hz, 0.5 mA, 1.5 mA) was applied to "Baihui" (GV 20) and "Dazhui" (GV 14) for 30 min, once a day (1 d) or once every 5 d for 10 times. The learning-memory ability was detected using Morris water maze tests (place navigation task and spatial probe trials), and the expression of Aβ 1-40 and AVP genes in hippocampal CA 1 region was determined using real time-PCR.
Results: In comparison with the sham group, the average escape latency of place navigation task, and the duration for crossing the target-platform for the 1 ^st time (spatial navigation task) were significantly increased ( P <0.05), and the times to cross the target-platform within 2 min (spatial probe trials) were significantly decreased in the model group ( P <0.05), suggesting a reduction of learning-memory ability. The expression level of Aβ 1-40 mRNA was remarkably increased ( P <0.05), and that of AVP mRNA notably decreased in the model group ( P <0.05). Following EA intervention, the increased escape latency and the duration of crossing the target-platform for the 1 ^st time and the increased Aβ 1-40 mRNA expression, and the decreased target-platform crossing times within 2 min as well the down-regulated AVP mRNA expression level were reversed in the 4 EA groups compared with the model group ( P <0.05). The therapeutic effects of higher stimulating intensity (1.5 mA-1 d-EA and 1.5 mA-5 d-EA) were markedly superior to those of lower intensity (0.5 mA-1 d-EA and 0.5 mA-5 d-EA), and the effects of higher frequency of EA intervention (0.5 mA-5 d-EA and 1.5 mA-5 d-EA) were obviously superior to those of lower frequency of EA (0.5 mA-1 d-EA and 1.5 mA-1 d-EA) in suppressing the increased 3 indexes and the decreased 2 indexes mentioned above ( P <0.05).
Conclusions: EA can improve the learning-memory ability of VD rats, which Feb be related to its effects in inhibiting the expression of Aβ 1-40 mRNA and up-regulating the expression of AVP mRNA in hippocampal CA 1 region; and the therapeutic effects of higher stimulating intensity and higher intervention frequency are obviously better than those of lower stimulating intensity and lower therapeutic frequency.