豚鼠脑震荡后耳蜗功能及螺旋神经节细胞的病理变化研究

Auditory function and pathological changes of spiral ganglion cells after cerebral concussion in guinea pigs

目的探讨脑震荡后耳蜗毛细胞功能以及螺旋神经节细胞的病理变化,为临床患者脑震荡后耳聋的诊治及法医学的鉴定提供一定的实验依据。方法选用听力正常的白毛红目豚鼠40只,雌雄不限,随机分为四组,分别为正常对照组、撞击后4周组、撞击后6周组和撞击后8周组。应用听性脑干反应(ABR)和畸变产物耳声发射(DPOAE)测试四组动物的听力和耳蜗功能,应用透射电镜观察各组耳蜗螺旋神经节细胞的病理改变。结果ABR阈值:撞击后4周、6周、8周组分别与正常对照组阈值比较均提高,差异有统计学意义(P<0.05);DPOAE结果:撞击后4周组与正常对照组在频率0.5kHz、0.7kHz、1kHz、2kHz比较有差异(P<0.05);撞击后6周组与正常对照组仅在频率4kHz比较有差异(P<0.05);撞击后8周组与正常对照组只在频率1kHz比较有差异(P<0.05)。透射电镜发现实验各组螺旋神经节细胞有不同程度的受损,表现为线粒体肿胀,空泡样变,线粒体嵴消失或位于周边,粗面内质网扩张等。结论脑震荡伤后可以引起ABR、DPOAE的异常和耳蜗螺旋神经节细胞的损伤。

Objective To investigate auditory function and pathological changes of spiral ganglion cells after cerebral concussion. Methods Forty healthy guinea pigs were randomly divided into four groups of 10 animals each： A （normal control）; B（four weeks post - concussion）, C（six weeks post - concussion）, and D（eight weeks post -concussion）. ABR and DPOAE were recorded, brain and spiral ganglion cell structure were examined by light microscopy and transmission electron microscopy（TEM）. Results Auditory threshold of ABR in group B, C and D showed a significant difference from that of control group A（P 〈 0.05）. The amplitudes of DPOAE at 0.5 kHz、0.7 kHz、1 kHz and 2 kHz in the group B were lower than that of normal control group A（P 〈 0.05）. The amplitude at 4 kHz in C group was lower than that of normal control group A（P 〈 0.05）. The amplitude at 1 kHz in D group was lower than that of normal control group A （P 〈 0.05）. The cell organs of spiral ganglion cells （SGCs） were injured severely in experimental groups. TEM revealed that mitochondria were swellen and degenerated with vacuolization , mitochondria crest disappeared or translocated to the edge. The rough surfaced endoplasmic reticulum was expanded. Conclusion Cerebral concussion can result in abnormal ABR and DPOAE and damaged SGCs.