神经生长因子基因转染联合强化铁营养防治豚鼠爆震性聋的实验研究

目的 探讨人类神经生长因子β基因(human beta-nerve growth factor,hNGFβ)转染联合强化铁营养(fortified iron nutrition,FIN)防治豚鼠爆震性聋的可能性.方法 制作强脉冲噪声(172 dBSPL)致聋豚鼠模型35只,爆震后第7天,10只豚鼠经耳蜗底周鼓阶骨壁钻孔向外淋巴腔内导入腺病毒携带hNGFβ基因(adenovirus-mediated hNGFβ,Ad-hNGFβ)为基因组,10只豚鼠导入hNGFβ基因并进行强化铁营养为联合组,10只豚鼠经耳蜗底周鼓阶骨壁钻孔向外淋巴腔内导入人工外淋巴液(artificialperilymphatic fluid,APF)为APF组.5只豚鼠作正常对照组,不经暴露噪声,也不用药物治疗.测定爆震前及基因转染后豚鼠脑干听觉诱发电位(auditory brain stem response,ABR)阈值.取材时间:基因导入后第1周及第4周实验组各取5只动物进行耳蜗取材,并进行免疫组织化学染色和HE染色,检测Ad-hNGFβ蛋白表达并进行螺旋神经节细胞计数.结果 基因导入后第1周,可见Ad-hNGFβ在耳蜗内成功转染.耳蜗各回均有表达,强度基本相等;联合组豚鼠ABR反应阈恢复较基因组快,较APF组明显快;4周后,联合组豚鼠ABR反应阈完全恢复正常,基因组基本恢复正常,APF组未能恢复;联合组豚鼠螺旋神经节细胞数目多于基因组,两者均明显多于对照组,计数结果差异有统计学意义(P<0.01),且细胞形态与正常相近.结论 腺病毒介导的hNGFβ基因联合强化铁营养能协同作用防治豚鼠爆震性听力损伤.

Protective effects of adenovirus-mediated human bta-nerve growth factor gene transfer combined with iron fortified nutrition on blast hearing damage in guinea pigs

Objective To study the protective effects of adenovirus-mediated human beta-nerve growth factor gene (hNGFβ) transfer combined with iron fortified nutrition on blast hearing damage in guinea pigs. Methods Deafness was induced by blast (172dB SPL) in 35 healthy guinea pigs. Seven days after noise exposure, 10 guinea pigs were inoculated with adenovirus-mediated hNGFβ (Ad-hNGFβ) into the perilymphatic space (the gene group), another 10 guinea pigs were given hNGFβ combined with iron fortified nutritional diet (the combination group), still another 10 guinea pigs were inoculated with artificial perilymphatic fluid (APF), and 5 guinea pigs served as control, given neither medicine nor noise exposure. Auditory brainstem response (ABR) threshold shifts were monitored in the guinea pigs before blast exposure and after gene transfer. Changes in cochlear morphology were examined with immunohistochemical and HE staining. Results One week after successful inoculation of hNGFβ, it was noted that Ad-hNGFβ protein was expressed in each turn of the cochlea, and its intensity was almost equal. After gene transfer in the combination group and the gene group, ABR threshold shifts at week 1 and 4 were significantly smaller than those of the APF group. HE staining showed that the number of the spiral ganglion cells in the combination group and the Ad-hNGFβ group was significantly higher than that of the control group after 4 weeks (P<0.01). Conclusions Ad-hNGFβ combined with iron fortified nutritional diet was effective in the prevention and treatment of blast hearing damage of cochlear hair cells.