豚鼠庆大霉素耳中毒后HSP70 mRNA的表达

为探讨热休克蛋白(heatshockprotein,HSP)70mRNA在庆大霉素(gentamicin,GM)耳中毒中的意义,本实验选用耳廓反射灵敏的健康白色红目豚鼠(200~250g)20只,雌雄不拘,随机分成两组,每组10只。实验组动物每日腹腔注射GM100mg/kg;对照组动物每日腹腔注射与GM等量的生理盐水2.5ml/kg。两组动物混合饲养,均连续用药10d。在用药前1天和停药后第1天进行听脑干反应(auditorybrainstemresponse,ABR)测试。各组豚鼠在行第二次ABR检测后,应用原位杂交及图像分析技术观察GM耳中毒后HSP70mRNA在豚鼠耳蜗中表达。结果显示:实验组耳蜗ABR阈值明显高于对照组,有显著性差异(P<0.01);实验组豚鼠耳蜗血管纹、螺旋韧带、螺旋神经节细胞HSP70mRNA表达呈强阳性,其平均灰度值较正常对照组明显减小(P<0.001),即GM能显著增强耳蜗HSP70mRNA的表达。结果提示,GM中毒后,动物可能通过增加HSP70mRNA在耳蜗的表达,起保护听力的作用。

Expression of heat shock protein 70 mRNA in guinea pig cochlea with ototoxicity of gentamicin

To examine the significance of heat shock protein 70 mRNA in ototoxicity resulted from gentamicin (GM), twenty healthyalbino guinea pigs (200~250 g) of either sex with a positive Prier reflex were divided into two groups randomly. In GM group the animalsreceived 100 mg/kg GM daily by intraperitoneal injection for 10 d. In saline control group the animals received 2.5 ml/kg saline dailyby intraperitoneal injection for 10 d. Auditory brainstem response (ABR) thresholds were recorded in each animal before and 1 d afterGM or saline administration. After the second ABR measurement, the expression of HSP70 mRNA in guinea pig cochlea was observedwith in situ hybridization and image quantitative analysis system. The results showed that the threshold of ABR in the GM group wassignificantly higher than that of the saline control (P<0.001). The expression of HSP70 mRNA was more intensive in stria vascularis,spiral ligament and spiral ganglion cells in the GM group than that of the saline control group. These results suggest that administrationof gentamicin can induce the expression of HSP 70 mRNA in guinea pig cochlea, and that this effect may protect hearing function fromototoxicity.