Effects of Repetitive Transcranial Magnetic Stimulation on the Abilities of Learning and Memory and the Cholinergic System of Hippocampus Formation in Rats with Vascular Dementia

Objective:To investigate the effects of repetitive transcranial magnetic stimulation(rTMS) on the abilities of learning and memory and the cholinergic system of hippocampus formation in rats with vascular dementia(VaD). Methods: Fifty-four male SD rats were randomly divided into control, VaD model and rTMS groups with 18 rats in each group. The VaD rats were established with two vessel occlusion method whereas bilateral carotid arteries were only exposed without ligation in the control group. The animals in the rTMS group were given rTMS treatment. The rats in the model group were treated by simulated rTMS and fixed head coil without impulse magnetic stimulation. Morris water maze(MWM) test was performed to evaluate learning and memory function of rats on the day 30 after two vessel occlusion. The activity of AchE and ChAT, the density of AChE-positive staining fiber and the expression of brain-derived neurotrophic factor(BDNF) in hippocampus were investigated. Results: The MWM escape latency in the rTMS group was shorter than that in the model group(P0.05). The number of crossing the corresponding platform during the same time period in platform quadrant in the rTMS group was significant more than that in the model group(P0.05). The activity of AchE and ChAT was decreased significantly in the model group compared with those in the control group, whereas it was improved significantly in the rTMS group(P0.05). The density of AChE-positive staining fiber and the expression of BDNF in the rTMS group were higher than those in the model group(P0.05). Conclusion: rTMS can ameliorate learning and memory deficit of rats with VaD, perhaps by way of increased expression of BDNF in hippocampus CA1 area and repair of hippocampal cholinergic system activity.