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目的探讨椎基底动脉缺血/再灌注耳蜗损伤后耳蜗病理形态学和听功能改变。方法经颅底径路建立豚鼠椎基底动脉缺血/再灌注耳蜗损伤模型。68只豚鼠随机分成6组:正常组、缺血1h组、缺血再灌注组(按再灌注时间分12h、24h、48h、7d,4组)。各组动物分别于手术前和处死前行听性脑干反应(auditory brainstem response,ABR)测定,观察ABR各波潜伏期、Ⅰ-Ⅲ波间期和Ⅲ波阈值,部分动物观察了缺血时ABR变化。耳蜗组织切片HE染色技术观察组织细胞形态变化。结果血管阻断缺血时ABR表现波形不典型,重复性差,在缺血10~20min后波形逐渐稳定;缺血组与再灌注(12h、24h、48h、7d)各组ABR各波潜伏期和Ⅰ~Ⅲ波间期较正常组延长,Ⅲ波阈值升高,尤以再灌注24h变化最为显著,48h和7d后ABR阈值有所恢复,但不能恢复正常。耳蜗病理形态学改变发现缺血组毛细胞变形肿胀,再灌注(12h、24h、48h、7d)各组损伤进一步加重,再灌注24~48h损伤最重,可见明显外毛细胞缺损,螺旋神经元胞体和神经纤维较正常组减少,血管纹变薄,均以基底转为明显。结论豚鼠椎基底动脉缺血/再灌注时可致耳蜗损伤,表现为听功能和耳蜗组织形态学改变。
Objective To investigate the pathological changes and auditory function of cochlea after vertebrobasilar ischemia / reperfusion injury. Methods The basilar approach was used to establish a cochlear injury model of guinea pig vertebrobasilar ischemia / reperfusion. 68 guinea pigs were randomly divided into 6 groups: normal group, ischemia 1h group, ischemia reperfusion group (according to reperfusion time 12h, 24h, 48h, 7d, 4 groups). The animals were respectively subjected to auditory brainstem response (ABR) before operation and sacrifice. The latency of ABR wave, Ⅰ-Ⅲ wave interval and Ⅲ wave threshold were observed. Some animals were observed ischemia ABR Variety. Cochlear tissue sections were stained with hematoxylin and eosin for histological observation. Results The waveform of ABR was not typical and had poor reproducibility during the period of vascular occlusion ischemia. The waveform was stable after 10 ~ 20min ischemia. The latency of ABR wave and the latency of ABR in ischemic group and reperfusion (12h, 24h, 48h, 7d) Ⅲ wave interval prolonged compared with the normal group, Ⅲ wave threshold increased, especially 24h after reperfusion the most significant change, ABR threshold 48h and 7d after recovery, but can not return to normal. Cochlear morphological changes found that the degeneration of the hair cells of the ischemic group, reperfusion (12h, 24h, 48h, 7d) further aggravate the injury in each group, reperfusion 24 ~ 48h the heaviest injury, visible defects of outer hair cells, spiral neurons Cell bodies and nerve fibers decreased compared with the normal group, vascular thinning, were basal turn to obvious. Conclusions Cochlear injury can be induced by ischemia / reperfusion of vertebrobasilar artery in guinea pigs, which is characterized by hearing function and cochlear morphological changes.