α_2-肾上腺素能受体在水杨酸钠诱导大鼠耳蜗螺旋神经节神经元兴奋毒性中的表达变化
Expression Changes of α₂-Adrenergic Receptor in Sodium Salicylate-induced Excitotoxicity of Rat Cochlear Spiral Ganglion Neurons
易健启;林晓宇;刘金兰;陈慧英;祝小婷;叶莞丽;黄佳琳;李睿琳;苏纪平
1:广西医科大学第一附属医院耳鼻咽喉头颈外科
2:广西中医药大学护理学院
摘要[Abstract] Objective To observe the distribution of α₂-adrenergic receptor (α₂-AR)in rat cochlear spiral ganglion neuron (SGN) and the expression changes of α₂-AR subtypes in SGN treated with sodium salicylate (SS) at different time points to explore its possible role in SGN excitotoxicity. Methods Newborn SD rats were randomly divided into 4 groups: control group, SS treatment for 6-hour group， SS treatment for 12-hour group and SS treatment for 24-hour group, with 2 rats in each group. After acute isolation of SGN from each group, primary culture was carried out for 48 hours. The expression of α₂-AR subtypes in SGN was detected by immunofluorescence staining, and the changes of mRNA and total protein expression of α₂-AR subtypes after SS treatment were detected by real-time fluorescence quantitative PCR(RT-qPCR) and Western blot. Results ①Immunofluorescence staining showed that there were three subtypes of α2A-AR, α2B-AR and α2C-AR on SGN. ②The results of RT-qPCR showed that the relative expression of mRNA of α2-AR subtypes in SGN was α2A-AR>α2B-AR, α2A-AR> α2C-AR,but there was no significant difference between α2B-AR and α2C-AR. Compared with the control group, the expression of α2A-AR increased significantly after treatment with 5 mM SS for 6 hours, 12 hours and 24 hours. After treatment with SS for 12 hours, the expression of α2C-AR began to increase, while the expression of α2B-AR showed an increasing trend, but the difference was not statistically significant.③Western blot results showed that the protein expression of α2-AR subtypes in SGN was α2A-AR >α2B-AR，α2A-AR >α2C-AR. There was no significant difference between α2B-AR and α2C-AR, which was consistent with mRNAexpression.Compared with the control group, the total protein of α2A-AR began to decrease after SGN was treated with 5 mM SS for 12 hours, and the total protein of α2C-AR decreased after 24 hours of treatment, while the total protein of α2B-AR remained unchanged.Conclusion Three subtypes of α2-AR were all expressed in SGN.α2A-AR and α2C-AR mediated SGN excitotoxicity induced by SS, and the response of α2A-AR was faster than α2C-AR.
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