表皮生长因子及地塞米松对爆震性聋治疗作用的实验研究

为研究爆震后豚鼠耳蜗毛细胞表皮生长因子受体（epidermalgrowthfactorreceptor，EGFR）的表达，以及表皮生长因子（epidermalgrowthfactor，EGF）及地塞米松（dexamethasone，DXM）的治疗效果，采用免疫组织化学ABC技术和听性脑干反应（ABR）检测。结果发现正常豚鼠耳蜗内、外毛细胞有散在的表皮生长因子受体（EGFR）表达，阳性反应位于听毛，呈节段性分布。爆震后24小时EGFR阳性反应分布于内毛细胞胞浆。爆震后72小时内毛细胞听毛和外毛细胞皮板呈阳性反应。震后1周内毛细胞阳性反应明显增多，部分外毛细胞听毛呈阳性反应。EGFR阳性反应至2周有所减少。震后1个月内、外毛细胞听毛均呈EGFR阳性反应。EGF及DXM对爆震性聋均有一定的治疗作用，二者合用可使豚鼠听力明显恢复。结果提示，毛细胞损伤修复可能与EGF有关。

Effects of epidermal growth factor and dexamethasone on blast hearing loss

The expression of epiderma1 growth factor receptor (EGFR) in cochlear hear cells was studied in normal and guinea pigs exposed to blasts. The effects of epidermal growth factor (EGF) and dexamethasone (DXM) treatment for blast hearing loss and the underlying mechanisms were also explored. Scattered expression of EGFR was seen in IHCs and OHCs in normal guinea. pigs. Segmentally distributing positive reaction was also located in stereocillia of hair cells. Distribu-tion of EGFR reaction was seen in the cytoplasm of IHC 24 hours after. exposure to blasts, and in the stereocillia of lHC and the cuticular plate of OHC 72 hours postexposure. At one week EGFR reaction in hair cells increased obviously and part of OHC stereocillia also showed positive reaction.EGFR reaction reduced at two weeks, though positive reaction could still be found in the stereocillia of hair cells at one month. Combination of EGF and DXM administrations promoted hearing recovery significantly. Our results suggest that healing of injured hair cel1s may be related to,EGF.