顺铂耳毒性小鼠模型的建立

Mouse Model of Cisplatin Induced Ototoxicity

【目的】建立一种可靠的、重复性好的顺铂耳毒性小鼠模型,为进一步从分子学和基因方面研究顺铂的耳毒性机制提供可能。【方法】20只听力正常的健康小鼠,随机平分为2组,A组小鼠先行200 mg/kg呋塞米腹腔注射,1 h后腹腔注射1.0 mg/kg顺铂;B组小鼠先行200 mg/kg呋塞米腹腔注射,1 h后腹腔注射0.5 mg/kg顺铂。6只同年龄小鼠做正常对照组。治疗后第10天所有小鼠行听觉脑干电反应(ABR)测听和畸变产物耳声发射(DPOAE)检查,之后取双侧耳蜗,分别行全耳蜗基底膜铺片和环氧树脂包埋半薄切片,观察内外毛细胞、血管纹和螺旋神经节细胞等的病变。【结果】2组小鼠治疗后各频率ABR平均听阈都提高,DPOAE值都降低,其中A组的ABR平均听阈显著提高,各频率振幅明显降低,高频区DPOAE消失;B组的ABR平均听阈稍提高,高频(16、20、32 kHz)振幅轻度降低,低频(4、8、12 kHz)振幅无变化,高频DPOAE稍下降,低频DPOAE无变化。全耳蜗基底膜铺片结果 A组蜗底外毛细胞全部破坏,蜗尖大部分外毛细胞破坏;B组仅蜗底外毛细胞大部分被破坏,蜗尖外毛细胞形态和数目接近正常,两组内毛细胞均无明显减少。半薄切片结果显示A、B两组小鼠的耳蜗血管纹和螺旋神经节细胞的形态和数目都接近正常。【结论】1.0 mg/kg顺铂联合200 mg/kg呋塞米单次腹腔注射法可引起小鼠内耳组织显著损伤,主要表现为耳蜗外毛细胞损失。

【Objective】To establish a reliable and reproducible mouse model of cisplatin induced inner ear hair cells loss and to make possible for further study of mechanisms of cisplatin-induced ototoxicity in mice from the molecular and genetic aspects. 【Methods】Twenty healthy mice were evenly divided into two groups in random. The mice in group A received a single dose of furosemide(200 mg/kg,intraperitoneal)followed by a single dose of cisplatin(1.0 mg/kg,intraperitoneal)1 h later,and the mice in group B received a single dose of furosemide(200 mg/kg,intraperitoneal)followed by a single dose of cisplatin(0.5 mg/kg,intraperitoneal)1 h later. Auditory brainstem response(ABR)and distortion product otoacoustic emission(DPOAE)were tested in both groups 10 d post the cisplatin-furosemide treatment and bilateral cochlea were taken out and fixed,one side cochlea were used for the surface preparation of total cochlear basal membrane and stained to count the number of cochlear hair cells from apex to base,the other was embedded with EPON812 gel and then cut into half thin slices. Six mice were used as control group.【Results】In both groups,the average ABR threshold of mice at each frequency were elevated,while the average DPOAE values were decreased. The average ABR threshold in group A increased significantly and the amplitude of each frequency decreased a lot,and DPOAE in high frequencies vanished;In group B,there was a minor elevation of ABR threshold with a slightly lower amplitude in higher-frequencies(16,20,32 kHz)but no amplitude change in lower frequencies(4,8,12 kHz)both in ABR and DPOAE. The surface preparation of Cochlear results in group A showed that nearly all the outer hair cells in the base had been destroyed,and most were destroyed in the apex;In group B,only the majority of cochlear outer hair cells at the base missed. There was no decrease of the numbers of the inner hair cells in both groups. Semi-thin cross-sections results also showed that the stria vascularis and spiral ganglion cells were close to normal in both groups.【Conclusion】Co-administration of single dose of 1.0 mg/kg cisplatin with a single dose of 200 mg/kg furosemide may induce significant loss of cochlear outer hair cells in mice.