不同剂量放射线对小鼠畸变产物耳声发射和外毛细胞Prestin蛋白表达的影响

摘要

目的 探讨单次不同剂量放射线照射对小鼠畸变产物耳声发射(DPOAE)和耳蜗外毛细胞Prestin蛋白表达的影响及放射线照射导致感音神经性聋的可能机制.方法 选取48只健康的Balb/c小鼠随机分成4组,每组12只(耳),分别给予0(对照组)、8(第1组)、12(第2组)、16 Gy(第3组)放射剂量的放射线照射,在照射后第7天对4组小鼠行DPOAE检测,同时分别采用Western-Blot分析和荧光实时定量中PCR检测4组小鼠耳蜗组织Prestin蛋白及Prestin mRNA表达的变化情况.结果 放射线照射第7天时,第1、2和3组小鼠3、4、6、8、10和12 kHz DPOAE幅值均较正常对照组小鼠明显降低(均P<0.05),正常对照组、第1、2和3组小鼠3、4、6、10、12 kHz DPOAE幅值依次减小(均P<0.05);第1、2和3组小鼠耳蜗组织Prestin蛋白及Prestin mRNA的表达均较正常对照组小鼠下降(均P<0.05),正常对照组、第1组、第2组和第3组小鼠耳蜗组织Prestin蛋白及Prestin mRNA的表达依次下降(均P<0.05).结论 单次放射线照射可损伤小鼠的听觉功能,使小鼠耳蜗外毛细胞Prestin蛋白及Prestin mRNA的表达下调,下调程度与照射剂量的大小呈正相关性;放射线致感音神经性听力损失可能与其导致耳蜗外毛细胞Prestin蛋白表达下调有关.%Objective To study the effect of different doses of radiation on distortion product otoacoustic e mission(DPOAE) and the Prestin protein expression in mouse cochlear outer hair cells, and explore the possible mechanism of radiotherapy(RT) induced sensorineural hearing loss(SNHL). Methods Forty-eight (28-day-old) mice were randomly divided into four groups(12 mice/group) ,in which received 0 Gy,8 Gy,12 Gy and 16 Gy radiation,respectively. The amplitudes of DPOAE were detected on the 7th day after RT(0 ,8 ,12 ,16Gy). And the expression of Prestin protein and Prestin mRNA in cochlears were detected by Western blot and the TaqMan based PT- PCR assays at the same time. Results The amplitudes of DPOAE of the mice after RT(8 ,10 ,12Gy) were low er than that of in the control mice at 3,4,6,8,10 and 12 kHz. The amplitudes decreased along with the increasing dose,which were significantly differente in statistics at 3,4,6,10,12 kHz. Compared with the normal mice,the ex pression of Prestin protein and Prestin mRNA were parallelly down-regulated in the other three radiation groups mice. Conclusion The auditory function was injuried and the expression of Prestin protein and Prestin mRNA were down - regulated in mouse outer hair cells after RT, which was positively correlated with the dose. The mechanism of SNHL after RT maybe correlated with the function expression abnormalities of the Prestin protein in the outer hair cells after RT.