目的：观察弥漫性脑外伤（diffuse brain injury ，DBI）大鼠听功能和耳蜗形态学的变化。方法 SD大鼠150只，随机分为正常对照组和DBI后1、2、3、4周组，每组30只。对照组不作任何处理，其他4组制作大鼠DBI模型，造模成功后，分别对各组大鼠进行ABR、40 Hz AERP、ASSR测试，并以光镜、电镜观察各组大鼠耳蜗形态学变化。结果 DBI后1周组的ABR、40 Hz AERP、ASSR阈值较正常组升高，第2、3周组阈值升高更明显，而在第4周组阈值略降低，DBI各组间及各组与对照组间比较差异均有统计学意义（均 P＜0．05）。电镜观察发现DBI 1周组耳蜗外毛细胞纤毛倒伏，线粒体嵴断裂或呈空泡变性；DBI 2、3周组外毛细胞纤毛倒伏明显，内线粒体空泡变性明显，而DBI 4周组耳蜗损伤改变减轻。结论弥漫性脑外伤可造成听功能受损及耳蜗超微结构损伤性变化。%Objective To study the changes of hearing function and cochlear morphology on diffuse brain in-jury model in rat .Methods One hundred and fifty SD rats with normal hearing were randomly divided into five groups ,each group consisted of 30 SD rats ,including a control group and four experimental groups which endured diffuse brain injury(DBI) from one to four weeks .Diffuse brain injury model of rats were established ,then ABR , 40 Hz AERP and ASSR examination ,light microscopy ,electron microscopy were used to evaluate the change of hearing function and morphology .Results The difference of ABR ,40 Hz AERP and ASSR thresholds between the experimental and the normal control group were significant (P<0 .05) .The thresholds of ABR ,40HzAERP and AS-SR were increased in the first week of DBI ,then the threshold continuously increased in the second and third week , at last the threshold decreased in the fourth week .The results under scaning electron microscope demonstrated that the ciliums of the majority of outer hair cells lodged in the first week of DBI .The results under transmission electron microscope showed that in the first week of DBI ,there were edema and denuration of mitochondrial ,mitochondrial cristaes were obscured or disappeared .The changes were deteriorate in the second and third week ,whereas the changes were mitigatal in the fourth week .Conclusion Cochlear morphology and hearing damage were observed in diffuse brain injury model of rats .
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