[Effects of simulated repeated transcranial acupuncture on learning and memory and cerebral microvascular flow in vascular dementia rats].

Objectives: To observe the effect of simulated repeated transcranial acupuncture (rTAS) on learning and memory abilities and cerebral microvascular flow in vascular dementia (VD) model rats, so as to explore the potential mechanism of rTAS in treating VD.

Methods: Thirty-two Wistar rats were randomly divided into normal, model, acupuncture and rTAS groups (=8 rats in each group). The VD model was established by permanent ligation of bilateral common carotid arteries. For rats of the acupuncture group, "Baihui" (GV20) and "Shenting" (GV24) were needled, and for rats of the rTAS group, GV20 and GV24 were stimulated by simulated repeated transcranial manipulation (200 r/min, for 5 min). The treatment was conducted once daily for 14 days. After the intervention, learning and memory abilities were evaluated using the Morris water maze test. Laser speckle technology was used to measure the average cerebral microvascular flow. ELISA was performed to measure the contents of vascular endothelial growth factor (VEGF), endothelin-1 (ET-1), nitric oxide (NO), and inducible nitric oxide synthase (iNOS) in the hippocampal tissues.

Results: In comparison with the normal group, the escape latency of rats in the model group was prolonged (<0.01), and the times of crossing the platform were decreased (<0.01). The average cerebral microvascular flow and the VEGF content in the hippocampus were significantly decreased, while the contents of NO, iNOS, and ET-1 were significantly increased (<0.01). In comparison with the model group, the escape latency was significantly shortened (<0.01), the average cerebral microvascular flow and VEGF content in the hippocampus were significantly increased (<0.05, <0.01), while contents of iNOS were significantly decreased (<0.05, <0.01) in both acupuncture and rTAS groups；and the times of crossing the platform were increased (<0.01), the contents of NO and ET-1 in hippocampus were significantly decreased (<0.01) in the rTAS group. The effects of rTAS were significantly superior to those of acupuncture in up-regulating the average cerebral microvascular flow (<0.05) and VEGF content (<0.01), and down-regulating the NO, iNOS and ET-1 contents (<0.01, <0.05).

Conclusions: rTAS can increase cerebral microvascular flow, improve spatial cognition and enhance learning and memory abilities of VD rats. The underlying mechanism may be involved in promoting angiogenesis, improving endothelial function and mitigating oxidative stress.