PNUTS在D-半乳糖诱导老化小鼠耳蜗中的表达

摘要

Objective To observe the expression of protein phosphates 1 nuclear targeting subunit (PNUTS) in the cochlea of D-galactose induced ageing mice. Methods Twenty Kunming mice, six weeks old, cleaning degree, were randomly divided into two groups, control group and D-galactose group, ten mice for each group. Mice in D-galactose group were administrated with D-galactose at a dose of 800 mg/(kg · d) by subcutaneous injection for eight weeks. Mice in control group were injected with the same volume of saline. After eight weeks, auditory brainstem responses (ABR) were collected to test the hearing thresholds of mice. Western blot assay was used to detect expressions of PNUTS and p53 protein. The expression and distribution of PNUTS in the cochlear Corti, spiral ganglion and striavascularis cells were observed by immunohistochemical (IHC) staining. Results There were no significant differences in ABRs at 8, 12 and 24 kHz between two groups. Protein expressions of PNUTS were located in the cochlear hair cells, spiral ganglion cells and striavascularis cells, and the expression level of cochlea was significantly decreased in D-galactose group than that in control group ( P<0.05). The expression level of p53 protein was significantly increased in D-galactose group than that in control group (P<0.01). Conclusion PNUTS is expressed in the normal mouse cochlea, and which is down-regulated in the cochlea of ageing mice induced by D-galactose.%目的：观察D-半乳糖诱导的老化小鼠耳蜗中蛋白磷酸酶1核目标亚基（PNUTS）的表达。方法6周龄清洁级昆明小鼠20只随机分为对照组和D-半乳糖组，每组10只。D-半乳糖组小鼠颈背部皮下注射D-半乳糖800 mg/（kg·d）；对照组颈背部注射等量生理盐水，均为每日1次，连续8周。造模完成后，进行听脑干反应（ABR）测试检测小鼠听力变化；取2组小鼠耳蜗，采用Western blot检测PNUTS及p53蛋白表达；免疫组织化学观察PNUTS蛋白在耳蜗毛细胞、螺旋神经节细胞及血管纹中的表达与分布情况。结果 D-半乳糖组小鼠在8、12、24 kHz这3个频率下的ABR阈值与对照组差异均无统计学意义。PNUTS蛋白在小鼠耳蜗毛细胞、螺旋神经节细胞及血管纹细胞中有表达，且D-半乳糖组小鼠耳蜗中PNUTS蛋白的阳性表达水平较对照组显著降低（P＜0.05）；而p53蛋白表达水平则显著升高（P＜0.01）。结论 PNUTS在小鼠耳蜗中有表达，且D-半乳糖能够诱导老化小鼠耳蜗中PNUTS表达下调。