重复经颅磁刺激对抑郁模型大鼠学习记忆功能及海马 CA3区突触素表达的影响

摘要

目的：观察重复经颅磁刺激（rTMS）对抑郁大鼠学习记忆功能及海马CA3区突触素（SYP）表达的影响。方法：SD雄性大鼠40只，随机分为对照组、抑郁组、rTMS组和伪刺激组，每组10只，后3组采用为期21 d的孤养结合慢性不可预见轻度应激制备抑郁模型。造模成功后，rTMS组给予3个疗程15 Hz的rTMS治疗；伪刺激组只施予同样次数的声音刺激而无电流脉冲。采用Morris水迷宫的定位航行实验及空间探索实验评定大鼠学习记忆功能。应用免疫组织化学方法检测大鼠海马CA3区SYP蛋白的表达情况。结果：4组大鼠逃避潜伏期、原平台象限游泳时间及原平台象限游泳路程占总路程的百分比及海马CA3区SYP蛋白表达水平比较，差异均有统计学意义（ F＝39．608、646．088、198．940、388．673，P＜0．001）。与对照组比较，抑郁组、伪刺激组大鼠逃避潜伏期延长，原平台象限游泳时间缩短，原平台象限游泳路程占总路程的百分比减小，SYP蛋白表达水平降低（P＜0．05）；与抑郁组、伪刺激组比较，rTMS组上述指标均明显改善（P＜0．05）。结论：rTMS干预可以改善抑郁模型大鼠的学习记忆功能，其机制可能与rTMS增加大鼠海马CA3区SYP的表达有关。%Aim:To investigate the effect of repetitive transcranial magnetic stimulation ( rTMS) on learning and mem-ory abilities, the expression of SYP protein in hippocampus CA3 region of depressed rats.Methods: Forty SD rats were randomly allocated into 4 groups:control group, depression group, rTMS group,and fake stimulation group,10 in each group.Rats in the latter 3 groups were given chronic unpredictable mild stress to establish depression model .rTMS group rats were given 15 Hz rTMS for 3 courses .Sham stimulation group were given only the same number of sound stimulation without electricity and current pulse .Then, Morris water maze test, including place navigation and spatial probe test , were performed to access the rats′learning and memory abilities , and the expression of SYP protein in hippocampus CA 3 was de-tected by immunohistochemistry .Results:There were significant differences in the escape latency ,the swimming time in o-riginal platform quadrant , the swimming distance percentage of total swimming distance in the original platform quadrant , and the expression of SYP protein in hippocampus CA 3 region among the 4 groups ( F =39.608,646.088,198.940, 388.673,P<0.001).Compared with the control group , the escape latency prolonged , the swimming time in original plat-form quadrant shortened , the swimming distance percentage of total swimming distance in the original platform quadrant re -duced, and the expression of SYP protein decreased in depression group and fake stimulation group (P<0.05).Compared with the depression group and fake stimulation group , the indexes mentioned above were improved ( P<0.05 ) in rTMS group.Conclusion:rTMS can improve the learning and memory abilities of depressed rats , the possible mechanism is in-creasing the expression of SYP in hippocampal CA 3 region.