目的 观察强噪声暴露后不同时期豚鼠耳蜗外毛细胞的死亡方式.方法 选用健康雄性白色豚鼠48只,随机分为健康对照组及噪声暴露后3 h、1 d、4 d、14 d、30 d组(实验组),每组8只,实验组动物暴露于120 dB SPL、4 kHz窄带噪声环境4 h,各组豚鼠于实验前及噪声暴露后相应时间点处死前测试听性脑干反应(auditory brainstem response,ABR),然后完成耳蜗基底膜铺片、Hoechst33342荧光染色,共聚焦荧光显微镜观察毛细胞核的变化并计数.对照组不作任何处理.结果 实验组噪声暴露后各组ABR反应阈明显高于对照组和噪声暴露前各组(P<0.01),实验组豚鼠耳蜗可见外毛细胞出现凋亡、坏死和缺失三种变化,噪声暴露后3 h、1 d、4 d组凋亡的细胞数明显多于坏死(P<0.05),噪声暴露后14 d组凋亡与坏死的细胞数没有明显差别(P>0.05),噪声暴露后30 d组坏死细胞数多于凋亡(P<0.05).结论 强噪声暴露后早期豚鼠耳蜗外毛细胞损害以凋亡为主,且凋亡过程迅速,耳蜗基底膜外毛细胞核的缺失主要源于凋亡细胞,强噪声暴露后中晚期外毛细胞损害以坏死为主.%Objective To study the cochicar outer hair cell death mode after exposure to intense noise at different stages. Methods Forty-eight guinea pigs were randomly divided into control group and 5 experiment groups (8 in each group) , the guinea pigs in the experiment groups were exposed to 4 kHz narrow band noise at 120 dB SPL for 4 hours. The animals were sacriticd at 3 hours, 1 days, 4 days, 14 days and 30 days after noise exposure rcapcctivciy. The auditory brainstcm rcsponsc(ABR) were tested in control group and experiment groups before being sacriticd. The changes of hair cells nucleus were studied by cochlea basilar membrane stretched prcparatin, Ho-chest 33342 staining and confocal fluorescence microscopy. Results Apoptosis, nccrois and hair cells missing were observed in experiment groups. The number of cells was significantly bisscr than nccrotic ones in 3 h,l d and 4 d groups (P<0. 05). No sigipont difference of cell humbcr was found between apoptosis and nccrotic cells in 14 d group(P>0. 05) ,however in 30 d group necrosis cells were more cells(P<0. 05) ; Conclusion In early stage, the apoptosis was the major change of OHCS after exposure to intense noise and it extremely rapid. The death of OHCs was mainly due to apoptosis and necrosis of the middle and late stage after noise exposure.
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