中文摘要：

目的：探讨次声对成年大鼠海马齿状回颗粒细胞下层（subgranular zone，SGZ）神经干细胞增殖抑制作用的细胞学机制。方法：成年雄性Sprague-Dawley大鼠置于次声压力舱，连续暴露于16Hz、130dB次声7d（2h／d）后，给与小胶质细胞抑制剂米诺环素（50mg／kg，药物组，n=16）或等体积生理盐水（对照组，n=16），同时设立不经次声作用的正常对照组（n=16）；分别于1、3、7和14d处死大鼠，利用免疫组织化学法以Iba1、OX42标记小胶质细胞，Brdu标记增殖的神经干细胞。结果：小胶质细胞在SGZ区分布较为密集；与正常对照组相比，次声暴露后3d时OX42免疫反应性明显增强、SGZ区BrdU阳性细胞数目减少最为明显（P〈0．01）；米诺环素可显著改善次声暴露后BrdU阳性细胞数目的减少（P〈0．01）。结论：小胶质细胞活化参与次声抑制成年大鼠海马SGZ区神经干细胞的增殖。

英文摘要：

Objective： To explore the cellular mechanisms underlying infrasound-induced suppression of neural stem cell proliferation in the subgranular zone （SGZ） of hippocampal dentate gyrus of adult rats. Methods： Male Sprague-Dawley rats were placed in a infrasonic chamber and exposed to 16 Hz at 130 dB infrasound for 2 h/d in consecutive 7 days. Then rats were treated with microglia inhibitor minocycline （ the drug group, 50 mg/kg, n = 16） or same volume of saline （ the control group, n = 16） intraperitoneally. The rats without infrasound exposure and drugs treatment were established as the normal control group （ n = 16）. At 1,3, 7 or 14 d following infrasound exposure, the rats were sacrificed and their brain sections were subjected to immunostaining of Iba1, OX42 （ two markers for mieroglia）, and BrdU （ a marker for proliferating cells）. Results： Microglia was distributed abundantly in the SGZ region. Relative to the normal controls, at 3 d following infrasound exposure, OX42 immunoreactivity was most enhanced and BrdU-positive cells were decreased to the lowest number in the SGZ （ P 〈 0.01 ）. Minocycline attenuated the infrasound-induced decrease of BrdU-positive cell number significantly （P 〈0.01 ）. Conclusion： Microglial activation was involved in infrasound-induced suppression of neural stem cell proliferation in hippocampal SGZ of adult rats.