强噪声引起的耳蜗毛细胞核形态学变化

NOISE-INDUCED MORPHOLOGIC CHANGES IN THE HAIR CELL NUCLEUS OF THE GUINEA PIG COCHLEA

为定量观察噪声引起的耳蜗毛细胞核形态学变化 ,将豚鼠暴露于 115dBSPL的 4kHz窄带噪声 4h。 14天后解剖取耳蜗 ,应用细胞核DNA染料Hoechst 3334 2标记毛细胞核 ,荧光显微镜下观察毛细胞核形态和数量的变化。结果发现 ,毛细胞核同时出现的 3种形态学改变 :核肿胀、核固缩和核消失 ,其中核肿胀细胞数目多于核消失 ,核固缩较为少见。爆震后毛细胞的损伤是一个复杂的、长期的、非同步的病理变化过程 ,存在较多核肿胀的毛细胞。提示 ,此期耳蜗可能仍存在大量可逆变化的受损毛细胞。

To observe the morphological changes in hair cell nuclei in guinea pigs following noise exposure, guinea pigs were exposed to 4 kHz narrow band noise at 115 dB SPL for 4h. The cochleae were collected for the examination of the hair cell nuclei 14 days after the noise exposure. A fluorescent dye, Hoechst 33342,a fluorescent dye, was used to label the nuclear DNA and the specimens were examined under a fluorescence microscope for quantitative assessment of hair cell nuclear damage. There were three types of morphological changes in the damaged hair cell nuclei: nuclear swelling, nuclear condensation (karyopyknosis) and nuclear missing. Nuclear swelling was more frequent than nuclear missing. Nuclear condensation was less frequently found. The results suggested that complicated, long term and non synchronous biological processes might be involved in noise induced hair cell damage. A large number of hair cells with swollen nuclei, which might recover afte wards,still could be seen in the cochlea two weeks after noice exposure.