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-Time PCR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5 ml/kg,1次/d,腹腔注射,连续5d),用药1d组(顺铂5 mg/kg,腹腔注射),用药3d组(顺铂5 mg/kg,1次/d,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-Time PCR、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.%Objective To investigate the effects of neurogenic differentiation (NeuroD) on spiral ganglion cells neu-rons(SGNs) in cisplatin-induced ototoxicity. 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 (5mg/kg, qd) for 1, 3 or 5 days, or equivalent volume 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 protein. Results This was a successful model of cisplatin ototoxicity, showing dynamic changes in expression of NeuroD in SGNs along with cisplatin administration. At day 1 and day 3 of cisplatin 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.
展开▼
