目的观察噪声损伤后耳蜗外毛细胞内单链DNA和EndoG的变化,探讨耳蜗外毛细胞的死亡机制。方法豚鼠随机分为噪声暴露组、MNNG耳蜗灌流组和对照组(每组各12只);小鼠随机分为噪声暴露组和对照组(每组12只)。分离解剖耳蜗后,用碘化丙啶(PI)...目的观察噪声损伤后耳蜗外毛细胞内单链DNA和EndoG的变化,探讨耳蜗外毛细胞的死亡机制。方法豚鼠随机分为噪声暴露组、MNNG耳蜗灌流组和对照组(每组各12只);小鼠随机分为噪声暴露组和对照组(每组12只)。分离解剖耳蜗后,用碘化丙啶(PI)染色细胞核、Pholloidin染色F-actin,免疫荧光抗体分别染色单链DNA(ssDNA)、核酸内切酶G(Endonuclease G EndoG)和凋亡诱导因子(Apoptosis inducing factors,AIF),制备耳蜗铺片,激光共聚焦显微镜下观察凋亡和坏死毛细胞内的荧光信号变化。结果(1)暴露于120dBSPL的白噪声环境中每天4小时,连续2天后引起豚鼠和小鼠耳蜗外毛细胞凋亡时,其细胞核内产生ssDNA,而在正常细胞内没有三ssDNA;(2)在正常情况下,EndoG分布于耳蜗毛细胞的细胞核外,在暴露于上述噪声后发生凋亡和坏死的豚鼠耳蜗外毛细胞中,EndoG从细胞核外转移到细胞核内,细胞核中的EndoG显著增加;(3)豚鼠耳蜗外淋巴灌流烷化剂MNNG后发生耳蜗外毛细胞凋亡和坏死,在凋亡和坏死的耳蜗外毛细胞中,AIF自线粒体转移到细胞核,其变化与噪声损伤引起耳蜗外毛细胞凋亡和坏死时一致。结论噪声刺激或烷化剂MNNG灌流后,造成耳蜗外毛细胞DNA损伤,产生ssDNA,引起AIF和EndoG自线粒体释放,激活Caspase-3,AIF和EndoG进一步向细胞核转移,最终使细胞核内的DNA降解,导致耳蜗毛细胞的死亡。展开更多
Alternating currents injected into the cochlea are able to evoke outer hair cell-mediated basilar membrane motion, thus give rise to production of otoacoustic emissions. This electrically evoked otoacoustic emission(E...Alternating currents injected into the cochlea are able to evoke outer hair cell-mediated basilar membrane motion, thus give rise to production of otoacoustic emissions. This electrically evoked otoacoustic emission(EEOAE) provides a useful tool for the research of out hair cell electromotility in vivo. This article reviews the research work on EEOAEs in mammals. Features of the EEOAEs and theories of their generation are introduced. Methods of EEOAE measurement are also described.展开更多
文摘目的观察噪声损伤后耳蜗外毛细胞内单链DNA和EndoG的变化,探讨耳蜗外毛细胞的死亡机制。方法豚鼠随机分为噪声暴露组、MNNG耳蜗灌流组和对照组(每组各12只);小鼠随机分为噪声暴露组和对照组(每组12只)。分离解剖耳蜗后,用碘化丙啶(PI)染色细胞核、Pholloidin染色F-actin,免疫荧光抗体分别染色单链DNA(ssDNA)、核酸内切酶G(Endonuclease G EndoG)和凋亡诱导因子(Apoptosis inducing factors,AIF),制备耳蜗铺片,激光共聚焦显微镜下观察凋亡和坏死毛细胞内的荧光信号变化。结果(1)暴露于120dBSPL的白噪声环境中每天4小时,连续2天后引起豚鼠和小鼠耳蜗外毛细胞凋亡时,其细胞核内产生ssDNA,而在正常细胞内没有三ssDNA;(2)在正常情况下,EndoG分布于耳蜗毛细胞的细胞核外,在暴露于上述噪声后发生凋亡和坏死的豚鼠耳蜗外毛细胞中,EndoG从细胞核外转移到细胞核内,细胞核中的EndoG显著增加;(3)豚鼠耳蜗外淋巴灌流烷化剂MNNG后发生耳蜗外毛细胞凋亡和坏死,在凋亡和坏死的耳蜗外毛细胞中,AIF自线粒体转移到细胞核,其变化与噪声损伤引起耳蜗外毛细胞凋亡和坏死时一致。结论噪声刺激或烷化剂MNNG灌流后,造成耳蜗外毛细胞DNA损伤,产生ssDNA,引起AIF和EndoG自线粒体释放,激活Caspase-3,AIF和EndoG进一步向细胞核转移,最终使细胞核内的DNA降解,导致耳蜗毛细胞的死亡。
文摘Alternating currents injected into the cochlea are able to evoke outer hair cell-mediated basilar membrane motion, thus give rise to production of otoacoustic emissions. This electrically evoked otoacoustic emission(EEOAE) provides a useful tool for the research of out hair cell electromotility in vivo. This article reviews the research work on EEOAEs in mammals. Features of the EEOAEs and theories of their generation are introduced. Methods of EEOAE measurement are also described.