噪声习服对听觉损伤的保护作用机制探讨

目的:探讨噪声习服对听觉损伤的保护作用机制.方法:建立噪声习服实验动物模型.采用免疫组织化学、激光扫描共聚焦显微镜(LSCM)及图像分析等技术,定量研究噪声习服后毛细胞内纤维状肌动蛋白(F-actin)、钙调蛋白(CaM)、热休克蛋白70(HSP70)的表达及游离Ca2 浓度的变化.结果:噪声暴露后毛细胞中F-actin、CaM及HSP70的表达均呈增加趋势.与噪声损伤暴露组(H组)比较,噪声习服后损伤暴露组(CH组)中F-actin和HSP70的表达均明显增多,CaM的表达具有增加趋势.声暴露后毛细胞内游离Ca2 浓度升高,噪声损伤暴露组毛细胞内游离Ca2 浓度明显高于噪声习服组(C组)和习服后损伤暴露组.结论:噪声习服使毛细胞对于其后声刺激的保护性反应增强,毛细胞内细胞骨架系统的加强及胞内钙稳态的维持在噪声习服的保护机制中具有重要意义.

The mechanism of protection by sound conditioning from acoustic trauma

Aim: To investigate the mechanism of protection by sound conditioning from acoustic trauma.Methods: Sound conditioning experimental model of animals was established.The expression of CaM,HSP70 and F-actin in hair cells were examined with the method of immunohistochemistry.Free calcium concentration in hair cells was observed by LSCM at the same time.Quantitative investigation was devised to assess the changes of F-actin,CaM,HSP70 and intracelluar calcium concentration in hair cells.Results: The expression of CaM,HSP70 and F-actin all showed an increased trend after noise exposure. HSP70 and F-actin expressed significantly more in group CH than that expressed in group H.Compaired with group H,the expression of CaM showed an increased trend in group CH.Elevation of intracellular calcium concentration could be resulted from noise exposure.The calcium concentration in group H was significantly higher than that in group C and group CH.Conclusion: A suitable sound conditioning can make the auditory system of guinea pig more resistant to noise trauma.The strengthened cytoskeleton system and the intracellular calcium homeostasis play a critical role in the protective mechanism of sound conditioning.