神经生长因子联合强化铁营养防治大鼠爆震性聋的实验研究

目的 探讨神经生长因子（nerve growth factor，NGF）联合强化铁营养（fortified iron nutition，FIN）防治大鼠爆震性聋的可能性。方法 制作强脉冲噪声致聋大鼠模型40只，于爆震前1周至爆震后2周，8只肌肉注射NGF，8只喂强化铁饲料，8只肌肉注射NGF并喂强化铁饲料，8只注射等量的生理盐水作对照，8只作正常对照。测定爆震前后脑于听觉诱发电位（auditory brain stem response，ABR）阈值，扫描电镜观察耳蜗毛细胞变化。结果 ABR反应阈：爆震后3d：联合用药组恢复较NGF组和FIN组快，较生理盐水对照组明显快，并于14d后已完全恢复正常，NGF组及FIN组明显恢复，而生理盐水对照组恢复不明显；扫描电镜示：爆震后3h：生理盐水组大鼠外毛细胞静纤毛排列扭曲、倒伏、紊乱、融合及部分缺失，NGF组及FIN组大鼠外毛细胞静纤毛有轻度紊乱及松散，联合用药组大鼠外毛细胞静纤毛有轻度紊乱；3d后：生理盐水组大鼠外毛细胞静纤毛病变无明显恢复，NGF组及FIN组大鼠外毛细胞静纤毛病变已减轻，联合用药组大鼠外毛细胞静纤毛病变已明显减轻；14d后：生理盐水组病变减轻，NGF组及FIN组病变明显减轻，还未完全恢复，联合用药组病变完全恢复。结论 NGF和强化铁营养能防止大鼠受损的毛细胞进一步变性和坏死，两者联合应用有协同作用，效果更明显。

The protective effects of nerve growth factor associated with fortified iron nutrition on blast exposure hearing damage in Wistar rats

Objective To study the protective effects of nerve growth factor (NGF) associated with fortified iron nutrition on blast exposure hearing damage in Wistar rats.Methods Forty Wistar rats models with blast exposure hearing damage were established and were divided into 5 groups:the 8 rats in NGF group were given nerve growth factor;the 8 rats in FIN group were given fortified iron nutritional diet; the 8 rats in combination group were given NGF associated with fortified iron nutritional diet;the 8 rats in NS group were given 0.9% sodium chloride for 3 weeks;and the 8 rats in the control group were given neither medicine nor noise exposure.ABR threshold shifts were tested in the rats before and after the blast exposure,and cochlear morphological changes were examined with scanning electron microscopy.Results The ABR threshold shifts in the NGF group,FIN group,combination group 3 h,3 d,14 d after the blast exposure were significantly smaller than those in the NS group.No permanent threshold shifts were seen in the NGF group,the FIN group and the combination group.Scanning electron microscopy indicated ghat the pathological changes of the outer hair cell stereocilia in the NGF group,the FIN group,and the combination group 3 h after blast exposure were less obvious than those in the NS group.After 14 d ,the stereocilia appeared perfectly normal and well defined in the combination group,whereas there were still remained some stereocilia abnormalities in the NS group.Conclusions NGF associated with fortified iron nutritional diet can obviously protect cochlear hair cell against blast exposure by decreasing degeneration and necrosis.