豚鼠冲击波负压暴露后耳蜗毛细胞损害定量观察

目的 探讨冲击波负压（blast underpressure,BUP）暴露后豚鼠耳蜗毛细胞损害特点.方法将豚鼠暴露实验性BUP 14天后处死,硝酸银染色硬铺片法计数观察耳蜗基底膜毛细胞损伤情况.结果压力峰值介于-22.4kPa和-63.3kPa之间的实验性BUP暴露后,豚鼠耳蜗外毛细胞出现了明显的病理性改变,损伤的程度以第二转最重,第二排和第三排的病变比第一排更为严重.BUP强度越高,毛细胞损害越重.各实验组动物的外毛细胞总缺失率明显高于正常对照组（P＜0.01）;重复暴露3次的动物外毛细胞缺失率明显高于暴露1次的动物（P＜0.01）.结论BUP暴露可引起明显的豚鼠耳蜗外毛细胞缺失等损害,其损害程度与负压峰值及暴露次数密切相关;毛细胞损害越重,ABR阈移也就越明显.

Quantitative study of cochlear hair cells injuries in guinea pigs exposed to blast underpressure

OBJECTIVE To explore the characteristics of cochlear hair cell injuries in guinea pigs exposed to blast underpressure(BUP). METHODS The guinea pigs were killed 14 days after exposure to experimental BUP. Their basilar membranes were stained by silver nitrate and the hair cell injuries were quantitatively assessed using the light microscope. RESULTS The outer hair cells(OHCs) of the guinea pigs clearly appeared to be injured following exposure to the experimental BUP at a peak underpressure varying between -22.4kPa and -63.3kPa. The most obvious injury was in the second turn and OHC loss was smallest in the first row and more severe in the second and third rows. OHC loss was seen in all of three experimental groups of animals following exposure to BUP. Furthermore, the higher the peak of underpressure, the more obvious the injury of OHCs. Quantitative morphological analysis of cochlear hair cells showed that the total OHC loss rates in all the experimental groups of guinea pigs exposed to BUP were significantly higher than that of control group animals(P<0.01). Also, the total OHC loss rates in the guinea pigs exposed to BUP for three times were significantly higher than that in guinea pigs exposed once (P<0.01). CONCLUSION The exposure to BUP may induce a loss of OHCs and pathological changes which are related to the peak of BUP and the times of exposure. The more severe the damage to OHCs, the greater the shift in ABR threshold.