β-肌动蛋白在雏鸡毛细胞再生修复过程中的变化

β-actin changes during hair cell regeneration in the chick basilar papilla

目的 探讨雏鸡基底乳头 (basilarpapilla ,BP)庆大霉素损伤后不同修复时间听毛细胞β 肌动蛋白 (β actin)和 β 肌动蛋白mRNA(β actinmRNA)的变化。方法 选 10d龄依沙褐种鸡 48只 ,36只给予庆大霉素 (每天 10 0mg/kg体重 )肌肉注射 ,连续 10d ,于停药后第 1、3、7、14、2 1和 2 8天各处死动物 6只 ,另 12只用作同期正常对照 ,每组 2只。分别应用免疫组化和原位杂交技术检测BP损伤区域β actin和 β actinmRNA表达状况 ,并对免疫组化和原位杂交染色进行计算机图像分析。 结果在停药后的 1、3、7d ,BP中 β actin免疫反应物呈现由阴性逐渐转为阳性反应的变化 ,至第 14天时 ,其阳性反应物强度接近或达到正常水平 ,以后增强缓慢。停药后第 7天 ,BP听毛细胞 β actinmRNA先于 β actin表达至高峰。结论 鸡BP损伤后 14d新生的毛细胞静纤毛已分化成熟 。

Objective To investigate the changes of β actin and β actin mRNA expression during hair cell regeneration in the chick basilar papilla(BP) following gentamicin ototoxicity. Methods Thirty six chicks were given muscular injection of gentamicin at dosage of 100 mg/kg·d for 10 consecutive days, and twelve additional chicks received injection of normal saline instead of gentamicin as controls. At 1,3,7,14,21 and 28 days after the treatment, six chicks in experimental group and two chicks in control group were sacrificed. Basilar papillas were prepared for immunohistochemistry and in situ hybridization study.β actin and β actin mRNA expression in the damaged region were histologically analyzed by computer image system. Results β actin immunoreactivity of BP changed significantly after treatment with gentamicin. From the first day to the fourteenth day after gentamincin,β actin immunoreactivity turned positive gradually. It approximated the normal response level at the fourteenth day after treatment of gentamincin. Then increasing rate of β actin immunoreactivity positive response level slowed from the fourteenth day after the treatment. At seventh day after treatment, β actin mRNA expression in BP increased to peak value, which preceded the peak expression of β actin in the regenerated hair cells. Conclusion Nascent hair cells seem to mature 14 days after hair cell damage, which may play a role in auditory functional recovery.