长期注射水杨酸钠对大鼠下丘GAD67和GABAAα1、c-fos表达的影响

Effect of sodium salicylate on the expression of c-fos,GAD67 and GABAAα1 in rat inferior colliculus

目的通过观察长期注射水杨酸钠对大鼠听性脑干反应(ABR)及下丘GAD67和GABAAα1、c-fos表达的影响,探讨大鼠下丘GAD67、GABAAα1、c-fos表达的改变在水杨酸钠耳毒性中的可能机制。方法将24只成年健康Wistar大鼠随机分为2组:水杨酸钠组(肌肉注射10%水杨酸钠175 mg/kg,2次/d,连续28 d)、对照组(每天相同时间注射等量生理盐水,连续28 d)。两组大鼠在处死前进行ABR检测并观察ABR反应阈及波Ⅲ潜伏期的变化,然后将大鼠断头处死并迅速剥离下丘,采用实时荧光定量PCR(real-time PCR)、蛋白质印迹(Western blot)方法检测下丘GAD67、GABAAα1、c-fos mRNA及蛋白表达的变化。结果 1药物注射28 d后,水杨酸钠组较注射前以及对照组ABR反应阈明显升高,波Ⅲ潜伏期明显延长,差异有统计学意义(P<0.01);2水杨酸钠组GAD67、GABAAα1、c-fos mRNA及其蛋白表达水平较对照组明显升高,差异有统计学意义(P<0.01)。结论GAD67、GABAAα1、c-fos均不同程度参与了水杨酸钠耳毒性的发生发展过程,c-fos表达的上调则可能与水杨酸钠作用于机体后引起听觉中枢神经活动增强有关。

Objective To observe the influences of sodium salicylate on the auditory brainstem response（ABR）and ex-pression of GA D67、GABAAα1、c-fos in rat inferior colliculus.To explore the underlying mechanisms of these changes on sodium salicylate induced ototoxicity.Methods Twenty-four Wistar rats were randomly divided into two groups：sodium salicylate group（intramuscular injection of 10%sodium salicylate,175 mg/kg,twice daily for 28 days）、control group（intramuscular injection with saline on same does at the same time）.The rats were detected ABR and observe the changes of ABR threshold before they were killed,then the rats were decapitated and inferior colliculus tissue were stripped.Real-time reverse transcriptase polymerase chain reaction（real-time RT-PCR）and Western blot were used to study the different expression of GA D67、GABAAα1、c-fos mRNA and protein level in the two groups.Results ①ABR threshold and latency of wave Ⅲ of sodium salicylate group was increased and prolonged remarkably than that of before administration and the control after injection for 28 days （P 〈0.01 ）;②The inferior colliculus GA D67、GABAAα1、c-fos mRNA and protein expression level of sodium salicylate group was significantly higher than the con-trol group（P〈0.01 ）.Conclusion In the long-term effects of sodium salicylate,the upregulation of GA D67 and GABAAα1 expression may occur as a compensatory and regulatory mechanisms for sodium salicylate ototoxicity,the elevated expression of c-fos may be associated with the increased activity of central auditory system after sodium salicy-late effects on the body.