A study regarding sensorineural hearing impairment with morphological changes in stria vascularis induced by the administration of Arg-Vasopressin

Wistar大鼠腹腔注射0.02单位/g的AVP（垂体加压素;精氨酸加压素）。Daiichi-Sankyo，Japan）在本研究的所有实验中。ABR阈值在注射后60 min内逐渐升高。当增加脱水负荷预处理24 h后，ABR阈值迅速显著升高，直至注射后10 min。光镜下未见耳蜗内淋巴积水的形态学改变。然而，在注射AVP后，在透射电子显微镜下检测到血管纹中的中间细胞中缺乏细胞内细胞器的区域或所谓的“空泡”的扩大。加入脱水负荷预处理24 h后，注射AVP使空泡面积增加。然而，当在AVP之前给予V2 R拮抗剂（OPC-31260，由Otsuka Pharmaceutical捐赠）时，空泡形成被显著抑制。相反，当在AVP注射前给予V1 aR拮抗剂（OPC-21268，由Otsuka Pharmaceutical捐赠）时，空泡形成没有受到抑制。

Wistar rats were intraperitoneally injected 0.02 units/g of AVP (Pitressin; Arg-vasopressin. Daiichi-Sankyo, Japan)in the all experiments in this study. ABR thresholds gradually increased significantly upto 60 min after the injection. When the dehydration load pretreatment for 24h was added, ABR thresholds rapidly increased significantly up to 10 min after the injection. However, the morphological endolymphatic hydrops in cochlea was not detected under a light microscopy. However, the enlargement of an area lacking intracellular organelles in the intermediate cells in stria vascularis or a so called “vacuole” was detected under transmission electron microscopy after the AVP injection. When the dehydration load pretreatment for 24h was added, the vacuole area increased with AVP injection. However, when the V2Rantagonist (OPC-31260, donated by Otsuka Pharmaceutical) was administered before AVP,vacuole formation was suppressed significantly. Conversely, vacuole formation was not suppressed when the V1aR antagonist (OPC-21268, donated by Otsuka Pharmaceutical) was administered before AVP injection.