增龄对年龄相关性听力减退大鼠听觉神经通路形态学的影响

Morphological study of the auditory neuropathway of Wistar rats with age-related hearing impairment

目的探讨年龄相关性听力减退大鼠听觉神经通路组织形态随增龄的变化。方法通过乙酰胆碱酯酶染色耳蜗基底膜铺片,蜗核、听皮层石蜡切片甲苯胺兰染色,比较3月龄和18月龄大鼠耳蜗底回的传出神经末梢数,蜗核、听皮层的神经元数量。结果18月龄大鼠耳蜗底回传出神经末梢较3月龄大鼠减少36%(P<0.01),缺失以2、3排外毛细胞为主;蜗核神经元减少24%(P<0.01);但听皮层神经元两组之间无显著差异(P>0.05)。结论年龄相关性听力减退大鼠听觉神经通路随增龄而退变。

Objective To explore the morphological changes of auditory neuropathway in Wistar rats with age-related hearing impairment. Methods Cochlear acetycholinesterase staining, cochlear nuclei and auditory cortex neurons toluidine blue staining were used in the morphological study of auditory neuropathway in Wistar rats of three-month-old and eighteen-month-old. Results Cochlear acetycholinesterase staining showed that the density of efferent nerve endings in the basal turn of eighteen-month-old rats was 36 less than that of the three- month- old rats （ P 〈 0. 01 ） , and the loss of nerve endings was found mostly at the second and third row of outer hair cells. The number of neurons of the cochlear nuclei in the eighteen-month-old rats were 24% less than that of the three-month-old rats （ P〈0. 05）. The distribution of neurons in the auditory cortex was insignifiantly different between the two groups （ P 〉 0, 05 ）. Conclusion Auditory neuropathway of Wistar rats with age-related hearing impairment is degenerated accompanied with the increase of age.