摘要
目的:观察条件声暴露对耳蜗结构损伤是否具有保护作用。方法:将听力正常的31只杂色雄性豚鼠(250~400g)按噪声暴露的时程不同随机分为四组,即条件声暴露1天组(n=8),条件声暴露7天组(n=8),条件声暴露14天组(n=7)及未经条件声暴露的对照组(n=8)。条件声为中心频率为1 kHz、强度为95 dBSPL的倍频程噪声,每天暴露8小时。条件声暴露结束5天后再将豚鼠暴露于相同频谱强度为115 dBSPL的强噪声中连续暴露48小时。强噪声暴露后第14天将动物处死,进行耳蜗铺片,观察各组动物耳蜗1 kHz感音部位第3回柯替器受损情况,并进行外毛细胞记数。结果:耳蜗铺片观察发现,1 kHz噪声损伤的主要部位为耳蜗第3回中下部,距圆窗约14 mm^18 mm处。外毛细胞(outer hair cellOHC)受损明显,三排OHC的受损程度以第三排最重,第二排次之,第一排最轻。内毛细胞(inner hair cell IHC)很少受损。四组动物中,以7天组外毛细胞丢失率为最少,为21.7%,明显低于对照组的32.2%(P<0.01)。其次为1天组,为29.5%,与对照组相比无明显差异(P>0.05)。而经过14天条件声暴露的动物,其OHC平均丢失率为34.4%,反而略高于对照组。结论:适当的条件声暴露对噪声引起的耳蜗结构损伤有一定的保护作用。
Objective ：To observe the protect effect of of different period of conditioning exposures on guinea pig＇s cochlear damage from noise trauma. Methods：Thirty -one guinea pigs served as subjects, the animals（ 250 -400 g） were randomly divided into four groups according to the duration of conditioning exposure（ animals were conditioning exposed to lkHz at 95 dBSPL wide band noise for 8 hours per day） , the first group（8 animals） received only one day（8 h） conditioning exposure, the second （8 animals） and the third group（7 animals） were conditioning exposed for 7 d（56 h） or 14 d（ 112 h） respectively, the fourth group（8 animals） received no conditioning exposure served as control group. Five days after the last ＂conditioning＂ exposure, all conditioned animals were re - exposed to the same spectrum at 115dBSPL for 48h, the control group animals were exposed only to the higher level noise, the co- chlear surface preparations were done on the 14th after the intense noise exposure. Results： Cochlear surface preparations indicated that the lesion was mainly on the third turn, about 14 mm - 18 mm from the round window. The outer hair cells（OHCs） were specially injured by noise whereas the inner hair cells were little affected, the second group animals showed significantly less hair cell loss than the other three groups（ P 〈0.05 ）. In the third group, the cochlear damage was more severe than the control group＇s. When the OHCs loss of the three raw was compared, OHCs loss in No. 3 raw was most severe, OHCs loss in No. 1 raw was least, OHCs loss in No. 2 raw between the two. ConcIusions： A suitable sound conditioning can protect the cochlea against intense noise trauma in morphological aspoct.
出处
《中国民康医学》
2006年第19期825-826,828,共3页
Medical Journal of Chinese People’s Health
关键词
条件声
坚韧化
耳蜗
毛细胞
Conditioning sound
Toughening
Cochlea
Hair cell
