中文摘要：

目的检测神经分化因子NeuroD在大鼠耳蜗螺旋神经元顺铂损伤后的表达变化。方法通过免疫组织化学及Real—TimePCR技术，观察耳蜗螺旋神经元损伤1d、3d、5d后NeuroD的表达变化。正常成年SD大鼠32只随机分为对照组（生理盐水5ml／kg，1次／d，腹腔注射，连续5d），用药1d组（顺铂5mg／kg，腹腔注射），用药3d组（顺铂5mg／kg，10Vd，腹腔注射，连续3d），用药5d组（顺铂5mg／kg，1次，d，腹腔注射，连续5d），每组8只，建立顺铂耳毒性模型。采用Real—TimePCR、免疫组织化学染色检测不同时间螺旋神经元NeuroD的mRNA及蛋白表达变化。结果成功建立顺铂耳毒性大鼠模型，随着用药时间的延长，神经分化因子NeuroD在耳蜗螺旋神经元中呈动态变化。NeuroD的mRNA和蛋白表达在用药1d及3d组分别为2．17~0．39、1．15~0．20及7．02~0．69、2．42~0．40，与对照组及用药5d组比较具有统计学意义（P值〈0．01）。结论NeuroD在用药1d后开始增加，3d后达到高峰，5d后下降；在用药早期有一过性表达增强，后期表达下降同时听力损失明显。表明NeuroD可能参与顺铂损伤螺旋神经元后的修复过程。

英文摘要：

Objective To investigate the effects of neurogenic differentiation （NeuroD） on spiral ganglion cells neu- rons（SGNs） in cisplatin-indueed ototoxieity. Methods Thirty two adult Sprague-Dawley（SD）rats were divided randomly into 4 groups （n--8 in each group） to receive intraperitoneal injection of cisplatin （Smg/kg, qd） for 1, 3 or 5 days, or equivalent vol- ume of saline （control group）. The mRNA level of NeuroD expression in cochlear tissues was examined by Real-Time PCR. The expressing pattern of NeuroD in damaged cochlea was studied by immunochemistry using antibodies against NeuroD pro- tein. Results This was a successful model of cisplatin ototoxicity, showing dynamic changes in expression of NeuroD in SGNs along with eisplatin administration. At day 1 and day 3 of eisplatin treatment, NeuroD mRNA levels were 2.17＋0.39 and 1.15 ~0.20, and NeuroD protein levels were 7.02~0.69 and 2.42~0.40, respectively, higher the control and 5 day treatment groups （P〈0.01）. Conclusions Expression of NeuroD seems to increase and peak at days 1-3 after cisplatin treatment, and decrease at day 5. This temporary increase at early stage followed by a later decrease （seemingly parallel to increasing hearing damage） may represent NeuroD＇ s role in the repair of SGNs following cisplatin-induced damage.