Beijing Da Xue Xue Bao Yi Xue Ban. 2017 Jun 18;49(3):501-505.
To observe the morphological changes on cochlear hair cells of rats in simulated weightlessness and inboard noise and to investigate the different changes in three turns of hair cells.
Thirty-two healthy SD rats, all males, were randomly divided into four groups: control group, weightlessness group, noise group and weightlessness+noise groups (n=8). Then rats were exposed to -30° head down tilt as simulated weightlessness and inboard noise including steady-state noise which was (72±2) dB SPL and impulse noise up to 160 dB SPL in spaceship environment. The control group was kept in normal condition for 8 weeks. Bilateral auditory brainstem response (ABR) thresholds were tested before and after exposure respectively, and immunofluorescence staining and scanning electron microscopy (SEMs) of basilar membrane were applied after exposure.
ABR threshold shifts of each group were higher after exposure. There was difference between ABRs of the experiment groups before and after exposure (P<0.05). IF showed that the inner hair cells (IHCs) missing was the main damage in the basal turn of weightlessness group, the hair cells in the middle turn were swell and in the top turn, the hair cells were not clear. In noise group, the main loss happened in the outer hair cells (OHCs) of the outermost layer. In weightlessness+noise group, the nuclear missing in the basal turn was apparent, and mainly happened at the outermost layer. Meanwhile, the missing of hair cells in the middle turn and top turn was seen at the innermost layer. SEM showed that the cilia in the basal turn of weightlessness group were serious lodging, and occasional absence. Furthermore, the basal cilia in noise group became lodged and absent, and the other two turns were seriously missing. And in weightlessness+noise group, the cilia missing in the basal turn was apparently seen. The damage degree of the four groups: weightlessness+noise group>noise group>weightlessness group>control group and the damage degree of the four turns of hair cells: basal turn>mid turn>top turn.
The rats exposed to the above environment for 2 weeks displayed obvious changes in cochlea morphology, and the weightlessness +noise group had the most obvious damage.
观察模拟失重及舱内噪声环境下大鼠耳蜗毛细胞的形态学变化，探讨毛细胞三个转区的不同变化情况。
将32只健康雄性SD大鼠随机分为四组：对照组、失重组、噪声组和失重+噪声组（n=8）。随后将大鼠置于-30°头低位倾斜状态模拟失重，并在飞船环境中给予包括（72±2）dB SPL的稳态噪声及高达160 dB SPL的脉冲噪声的舱内噪声。对照组在正常条件下饲养8周。分别在暴露前后检测双侧听性脑干反应（ABR）阈值，并在暴露后进行基底膜的免疫荧光染色及扫描电子显微镜（SEM）检查。
暴露后各组ABR阈值变化均升高。实验组暴露前后ABR有差异（P<0.05）。免疫荧光显示，失重组基底转区主要损伤为内毛细胞（IHC）缺失，中转区毛细胞肿胀，顶转区毛细胞不清晰。噪声组主要损失发生在最外层的外毛细胞（OHC）。失重+噪声组基底转区细胞核缺失明显，主要发生在最外层。同时，中转区和顶转区毛细胞缺失见于最内层。扫描电子显微镜显示，失重组基底转区纤毛严重倒伏，偶有缺失。此外，噪声组基底纤毛倒伏、缺失，其他两个转区严重缺失。而在失重+噪声组，基底转区纤毛缺失明显可见。四组损伤程度：失重+噪声组>噪声组>失重组>对照组；毛细胞四个转区损伤程度：基底转>中转>顶转。
暴露于上述环境2周的大鼠耳蜗形态出现明显变化，失重+噪声组损伤最为明显。
