压力波对豚鼠耳蜗降钙素基因相关肽免疫反应(CGRP-IR)及听阈的影响

Effects of Explosion on Calcitonin Gene-Related Peptide Immunoreactivity (CGRP-IR) of Guinea Pig Cochlea and Hearing Threshold

豚鼠暴露于152加农炮发射—发(178dB,SPL)后24、72小时、1、2周和1月,用ABC法结合葡萄糖氧化酶-DAB-硫酸镍铵(ABC-GDN)行耳蜗CGRP免疫组化染色,反应产物用图象分析仪行定量测定,并记录震后不同时间ABR阈值,以探讨爆震后中耳损伤及耳蜗内、外毛细胞区CGRP-IR的变化与听阈的关系。结果提示爆震后中耳有损伤者阈移有减小的倾向。外毛细胞区含CGRP神经较内毛细胞区更易受损。橄榄耳蜗束(OCB)中CGRP对听功能有一定的保护作用。CGRP的减少可能降低了耳蜗对听损伤的耐受性。

Guinea pigs were exposed to 1 shot of cannon, with a peak pressure at 178dB(SPL). The Avidin-Biotin peroxidase complex immumostaining in combination with glucose oxidase-DAB-nichel enhancement technique was used to investigate the changes of CGRP immunoreactivity(CGRP-IR)in inner and outer hair cell regions of auditory cochlea. The optical densities of the CGRP-IR in the cochlea were quantified with the image amalysing technique and the ABR threshold was measured 24h、72h、1、2 week and 1 month after the exposure. The relationship of ABR threshold shift with the middle ear damage and changes of CGRP-IR in the inner and outer hair cell regions were studied.The results sugessted that ABR threshold shifts of the ears with middle-ear damage tended to be less than that with normal middle-ear after one exposure. The CGRP-eontaining fibers in the outer hair cell regions are more sensitive to the blast injusy than that in the inner hair cell regions. This is well in accordance with the rule of blast injusy on hearing organ. CGRP in the olivocochlear bundle may partly protect hearing function from the injusy due to blast damage. The decline of GCRP may increase the susceptalility of hearing organ to the blast injusy.