重复经颅磁刺激对脑缺血后神经干细胞增殖以及miR一9表达的影响

The effect of transcranial magnetic stimulation on the proliferation of neural stem cells and miR-9 in thebrain after focal cerebral ischemia

目的观察重复经颅磁刺激（rTMS）对急性脑缺血大鼠室管膜下区（SVZ）神经干细胞增殖和微小核糖核酸一9（miR一9）表达的影响，探讨rTMS治疗急性脑缺血的可能机制。方法将雄性SD大鼠按随机数字表法分为假手术组、对照组和rTMS组，采用短暂性大脑中动脉阻塞（tMCAO）法制作急性脑缺血大鼠模型。假手术组和对照组没有进行任何治疗；rTMS组从术后1d开始给予患侧大脑磁刺激治疗（10Hz，120％静息运动阈值，单序列30个脉冲，间隔50s，共10个序列），每日1次，共治疗7次。治疗结束后，使用免疫组织荧光化学法检测患侧SVZ的溴脱氧尿苷（BrdU）／巢蛋白（nestin）双阳性细胞以分析神经干细胞增殖情况，并通过实时定量聚合酶链式反应（qRT—PCR）检测患侧脑组织miR-9表达量。结果治疗7d后，对照组患侧SVZBrdU＋nestin＋细胞数较假手术组增高（P〈0．05），rTMS组较其它两组显著增高（P〈0．05）。同时，对照组患侧脑组织内miR一9表达显著低于假手术组（P〈0．05），rTMS组miR一9表达均显著低于其它2组（P〈0．05）。结论rTMS治疗可促进急性脑缺血大鼠SVZ神经干细胞增殖，且抑制患侧脑组织miR一9表达。

Objective To investigate the effect of repetitive transcranial magnetic stimulation （rTMS） on the proliferation of neural stem cells in the subventricular zone （SVZ） and the expression of miR-9 in the ipsilesional hemisphere of rats with focal cerebral ischemia. Methods A rat model of acute focal cerebral ischemia was estab lished using transient middle cerebral artery occlusion （tMCAO）. Rats were then randomly assigned to a sham group, a control group or an rTMS group. Daily rTMS treatments （ 10 trains with 30 pulses per train and 50-second breaks between trains at 120% of the resting motor threshold） were targeted at the ipsilesional M1 cortex beginning one day after the tMCAO. After the treatment the proliferation of neural stem ceils in the ipsilesional SVZ was identified by double immunofluorescence staining （ BrdU/nestin）. The expression of miR-9 was evaluated using quantitative PCR. Results Compared with the other two groups, BrdU ＋ Nestin ~ cells in the ipsilesional SVZs of the rTMS group in creased and the expression of miR-9 decreased significantly. Conclusion rTMS can promote the proliferation of neural stem cells and inhibit the expression of miR-9 in the ipsilesional hemisphere after focal cerebral ischemia.