模拟飞船舱内中长期失重及噪声复合因素对大鼠听器官的影响

目的　探讨模拟飞船舱内2～8周的中长期失重及噪声复合因素对大鼠脑干诱发电位和耳蜗结构的影响。方法　健康成年大鼠随机分成雄性实验及对照组、雌性实验及对照组。实验组暴露于模拟失重及稳态噪声环境中，实验结束前给予脉冲噪声暴露；对照组不施加因素。分别于实验前、实验第2、4、8周及脉冲噪声暴露后检测双侧听性脑干反应阈值（ABR），并行扫描电镜观察。结果　两实验组内脉冲噪声暴露后ABR阈值明显增高（P 均＜0.05）；实验后2、4周ABR阈值雌性实验组均较雄性实验组低（P 均＜0.05），扫描电镜观察发现内外毛细胞缺失，大片倒伏，随着复合因素作用时间延长耳蜗毛细胞病理性改变加重。结论　中长期失重噪声复合因素可造成大鼠听功能损害，且脉冲噪声比稳态噪声更明显；损害存在性别差异；大鼠耳蜗毛细胞病理性改变随复合因素时间延长而加重。

Effects of simulated noise-weightlessness combined factors in spaceship on auditory function of rats after a medium-long term

OBJECTIVE To investigate the effects of simulated noise-weightlessness combined factors on auditory brainstem response thresholds and the cochlear structure after a medium-long term (2-8 weeks). METHODS Healthy adult rats were randomly divided into male/female experimental and control groups. The male and female experimental groups were exposed to simulated noise-weightlessness environment and exerted impulse noise exposure at the end. Auditory brainstem response (ABR) threshold was recorded at the beginning, the 2nd, 4th and 8th weeks and after impulse noise exposure exerting. The cochlea was also examined by scanning electron microscopy each time after ABR threshold record. RESULTS ABR thresholds in experimental groups after impulse noise exposure were significantly increased (P<0.05). Female experimental group were lower than those of the male experimental group at 2 and 4 weeks (P<0.05). Scanning electron microscope observation showed that the inner and outer hair cell were losing and lodging, and the longer exposed to the compound factors, the heavier pathological changes observed on the cochlear hair cell. CONCLUSION Noise-weightlessness combined factors can cause the morphology and function damage of rat cochlear in medium-long term. The damage of impulse noise was more than steady noise on rat auditory function. Sex differences was also observed. Rat cochlear hair cell pathological changes increased with the exposed time.