两种噪声刺激对豚鼠听觉早期损伤的比较

Comparison of Two Stimulant Noises in their Potential Early Hearing Damages to Guinea Pigs

目的比较相同强度的不同噪声刺激后豚鼠听力和耳蜗外毛细胞损伤程度。方法将19只豚鼠分为娱乐噪声组(8只)、白噪声组(7只)和正常对照组(4只),白噪声组和娱乐噪声组声刺激平均强度均为105dBSPL,5小时/天,连续给声刺激5天。各组豚鼠在给噪声前及连续给噪声刺激5天结束后进行ABR和DPOAE检测,并在测试结束后取耳蜗应用异硫氰光素标记的鬼笔环肽(phalloidin-FITC)标记表皮板和静纤毛,应用碘化丙啶(PI)标记外毛细胞核,在激光共聚焦显微镜下观察毛细胞受损情况(包括核肿胀、核固缩、核缺失)。结果白噪声组和娱乐噪声组两种噪声刺激前后豚鼠ABR阈值分别为17.5±3.80、16.88±4.03dBSPL和64.64±5.36、45.94±4.55dBSPL;两组刺激前后DPOAE幅值均有所下降(P<0.05),且白噪声组比娱乐噪声组更为明显。白噪声组可观察到大量核肿胀和核固缩的外毛细胞及核缺失的毛细胞,娱乐噪声组观察到受损外毛细胞以核固缩为主,损伤总数远远低于白噪声组。结论相同强度白噪声和娱乐噪声刺激均可造成豚鼠一定程度的听力损失,娱乐噪声刺激后外毛细胞损伤以早期病变为主,其受损程度低于白噪声组。

Objective To compare the early damage of heating level and cochlea outer hair cells after exposed to different noise at same intensity in guinea pigs. Methods 19 guinea pigs were grouped randomly into recreational noise group（8）, WN （white noise） group（7） and normal grouP（4 ）. The recreational noise and WN groups were exposed to the noise at the same intensity of 105 dB SPL for consecutively 5 days（5 hours per day）. Auditory brainstem response （ABR） thresholds and distortion product otoacoustic emission（DPOAE） were mesured bofor and after noise exposure （0 d and 5 d ） .After the mesttrement,the organs of corti were processed for detection of hair cell injury with double - stain using Frrc labeled phalloidin for filamentous actin（F - actin） and propidium iodide（PI） for hair cell nuclei. The structure changes of cochlea hair cells , such as nuclei swelling, nuclei condensed, nuclei missing, were observed using a laser scanning confocal micrescope（LSCM）. ReSults The ABR thresholds of the guinea pigs exposed to recreational noise and WN was 17.5 ± 3.80,16.88 ± 4.03 dB SPL before esposure and 64.64 ± 5.36,45. 94 ± 4.55 dB SPL after exposure. The guinea pigs exposed to different noise both showed a significant decrease of DPOAE level（ P 〈 0.05）, espicially the guinea pigs from WN group. Laser scanning confocal micrescope showed that a great quantity of outer hair cells in WN group displayed nuclei swelling, nuclei condensed and nuclei missing . Outer hair cells in recreational noise group mainly displayed nuclei condensed, and the total number of injuried hair cells was obviously less then WN group. Conclusion Recreational noise and white noise at the same intensity both can induce some heating loss. The outer hair cells show early injury after being exposed to recreational noise, and are not as seriously as that being exposed to white noise.