Effects of repetitive transcranial magnetic stimulation on learning, memory and dendrite morphology in the hippocampus / 中华物理医学与康复杂志

ABSTRACT

Objective To survey the effects of repetitive transcranial magnetic stimulation (rTMS) on learning,memory and the dendrite morphology of neurons in the CA1 area of the hippocampus in rats with vascular dementia.Methods Thirty-six male SD rats were divided into a control group,a model group and a rTMS group randomly,12 rats in each group.A model of vascular dementia (VaD) was established using the two vessel occlusion method.The rats in the rTMS group were given rTMS treatment.The rats in the other two groups had no therapy.The Morris water maze (MWM) test was used to evaluate the rats' learning and memory abilities on the 30th day after the operation.After the MWM test the dendrite morphology of the pyramidal cells in the CA1 area of the hippocampus was detected after Golgi-Cox staining using light microscopy and the expression of brain-derived neurotrophic factor (BDNF) was detected using immunohistochemistry methods.Results The average MWM escape latency in the rTMS group was shorter than in the model group on the 1 st,2nd,3rd and 4th day.The number of crossings of the platform quadrant in the rTMS group was significantly more than in the model group.The number of branch segments,their total length and the dendritic spine density of pyramidal cell dendrites in the CA1 area of the hippocampus were all significantly lower in the model group than in the control group,but in the rTMS group all these indicators were significantly improvedcompared with the model group.The expression of BDNF in the CA1 area in rTMS group was significantly higher than in the model group.Conclusions rTMS can improve learning and memory in VaD,at least in rats.The mechanism may be associated with rTMS promoting the expression of BDNF in the hippocampus and so improving the dendrite morphology of pyramidal cells.