Objective To investigate the effects of early air-conduction deprivation(AD) on the development of basilar membrane and auditory brainstem response (ABR) in rats. Methods The deprivation group with plugging in the external acoustic meatus from 12 days postnatal, raised in a soundproof room, and then removed the deprivation after 42 days. The control group were raised normally. Both groups were tested for ABR thresholds and observed the morphology of basilar membranes by a scanning electron microscope at different time postnatal. Results The average of ABR threshold in the control group decreased gradually with age. ABR thresholds of the AD group were significantly increased after 35 days postnatal compared with control group. The average thresholds of AD group were 39.47, 38. 20 and 39.07 dB SPL at 35, 42 and 56 days postnatal, respeotively,and there was little recovery of ABR thresholds after removing of the plugging. Morphology observation of basilar membrane of the control group showed that the cilia of outer hair cells arranged in order, while that of the AD group have plenty of vesicles on the cells surface, outer hair cells were found swelling in the cilium end. Conclusion Auditory afferent is necessary for the postnatal auditory development in rats. Early air-conduction deprivation can affect the auditory development of rats.%目的 研究早期气导听觉剥夺对大鼠听性脑干反应(ABR)和Corti器基底膜发育的影响.方法 SD仔鼠共60只,随机分为听觉剥夺组及对照组,每组30只.听觉剥夺组行双外耳道填塞后饲养于密闭隔声室,对照组在正常声音环境饲养,两组动物分别于出生后21、28、35,42及56天时行ABR检测,42及56天时应用扫描电镜观察Corti器基底膜发育情况.结果 对照组大鼠ABR反应阈随年龄增长呈下降趋势,56天时为24.17 dB SPL,基本达到正常成年大鼠水平,听觉剥夺组大鼠随饲养时间延长ABR反应阈较对照组明显增高,35天时增高至39.47 dB SPL,去除双外耳道填塞物后ABR反应阈无明显恢复.扫描电镜可见对照组Corti器基底膜外毛细胞纤毛排列整齐,听觉剥夺组基底膜外毛细胞表面形成大量细小囊泡,纤毛末端膨大、融合.结论 出生后早期气导听觉剥夺可造成大鼠Corti器基底膜发育异常以及听觉障碍,表明气导听觉传入在听觉发育过程中起着十分重要的作用.
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