Objective To explore the effects of repetitive transcranial magnetic stimulation (rTMS) on the improve⁃ment of depressive behavior and the hippocampus brain derived neurotrophic factor (BDNF) expression in chronic stress-induced depression rats. To further investigate the possible molecular mechanism of rTMS treatment for depres⁃sion. Methods Forty male Sprague-Dawley rats of SPF grade were randomly divided into the blank control group (n=8) and the stress-induced group (n=30). Singly housing and chronic unpredictable mild stress (CUMS) were used to induce the depression model in stress-induced group. Twenty-four model rats were divided into three groups:model group (with no further treatment), rTMS group (receiving 10 Hz rTMS intervention for 3 weeks) and shame group (receiving pseudo TMS treatments for 3 weeks). Weight measurement, sucrose consumption test and open-field test were used to assess the behavior changes. The rat hippocampal CA3 area of BDNF positive staining cell number and expression levels of BDNF mRNA in hippocampus were examined after intervention. Results The weight reduction rate, score of sucrose consump⁃tion test and the score of open field test were significantly higher in rTMS group than in model group (P<0.05). The num⁃ ber of BDNF staining positive cells in the hippocampal CA3 area was lower in model group and shame group than in the blank control group whereas was higher in the rTMS group than in the model group (P<0.01). Compared with the model group, the BDNF mRNA relative expression was significantly increased in the hippocampus of rTMS group (P<0.01). Conclusion rTMS can improve depressive behaviors of CUMS rats probably through the increase in expression of BDNF in the hippocampal neurons and neuronal regeneration.%目的：探讨重复经颅磁刺激（repetitive transcranial magnetic stimulation，rTMS）对慢性应激抑郁模型大鼠行为学及海马脑源性神经营养因子（brain derived neurotrophic factor，BDNF）的影响，探讨rTMS抗抑郁作用的可能机制。方法40只雄性SPF级Sprague-Dawley大鼠经过初次筛选后，随机分为造模组（n=30）和空白对照组（n=8），造模组应用孤养联合慢性不可预见性温和应激（chronic unpredictable mild stress，CUMS）方法建立大鼠抑郁模型，筛选造模成功的大鼠24只随机分为rTMS组、伪刺激组和抑郁对照组，每组8只，抑郁对照组不给予rTMS干预，rTMS组和伪刺激组分别接受10 Hz的rTMS刺激和伪刺激干预3周。分别于造模前、造模后和干预后进行体质量测量、蔗糖水消耗实验和旷场实验评估，在干预后，检测大鼠海马CA3区BDNF阳性染色的细胞数及海马BDNF mRNA的表达水平。结果造模后，rTMS组、伪刺激组和抑郁对照组大鼠的体质量减分率较空白对照组降低（P<0.01），体质量增加缓慢（P<0.01）。干预后，rTMS组大鼠体质量减分率、蔗糖水消耗量、旷场实验的水平运动评分以及垂直运动评分较伪刺激组和抑郁对照组均增高（均P<0.05），与空白对照组差异并无统计学意义（均P<0.05）。干预后，rTMS组大鼠海马CA3区BDNF阳性细胞数目较伪刺激组和抑郁对照组增加（P<0.01），伪刺激组和抑郁对照组较空白对照组减少（P<0.01）；rTMS组大鼠海马BDNF mRNA的相对表达量较伪刺激组和抑郁对照组增多（P<0.01），伪刺激组和抑郁对照组较空白对照组减少（P<0.01）。结论 rTMS干预能够改善CUMS抑郁模型大鼠的抑郁样行为，可能与增加海马BDNF的表达导致海马神经元再生有关。
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