电针对水杨酸钠耳鸣模型大鼠中枢听觉系统的影响及机制研究

Acupuncture is a traditional treatment for tinnitus, but the mechanisms need to be further illuminated. This project aim to investigate and discuss the efficacy and mechanism of acupuncture as a possible cure for tinnitus. We select the acupoints Tinggong + Yifeng or Waiguan + Zhongzhu, for they are the basic acupoints in the clinical treatment. We construct the chronic tinnitus model by systemic sodium-salicylate treatment to the rats for continuous 5 days. Using the gap prepulse inhibition acoustic startle reflex (GPIAS) , we inspect the effect on the tinnitus-related behavior with or without electroacupuncture. By using the electrophysiological extracellular recording, we inspect the influence of electroacupuncture on the tinnitus-related abnormal neural electro-activity in the central auditory pathway, both the spontaneous and sound-evoked responses, including the spontaneous firing rate (SFR),frequency-level recptive field(FLRF),intensity tuning curve(ITC) and the poststimulus time histogram(PSTH) of the auditory neurons in auditory cortex (AC), medial geniculate body (MGB) and the inferior colliculus (IC). We also record the spontaneous and sound-evoked responses after nucleus accumbens (NAc) electro-stimulation to explore what role the limbic system might play in the electroacupuncture treatment. Finally,by using Western-blot and real time-PCR, fluorescent immunohistochemistry technics, we quantify the changes of certain molecules which might serve as the mechanisms that underly the effects of the electroacupuncture treatment. The molecules include the immediate early gene c-fos and arc/arg 3.1,the brain-derived neurotrophic factor (BDNF), the N-methyl-D-aspartate (NMDA) receptor and gamma-aminobutyric acid A (GABAA) receptor in the auditory brain and limbic system.

以慢性水杨酸钠大鼠为耳鸣模型，选取临床治疗耳鸣基本穴位听宫+翳风，外关+中渚。采用声惊吓反射前脉冲抑制行为测试（GPIAS），考察电针穴位对水杨酸钠大鼠耳鸣相关行为的影响效应；以神经电生理学研究方法，考察电针穴位对中枢听觉系统听皮层（AC）、内侧膝状体（MGB）及下丘（IC）自放电率（SFR）、频率强度感受野（FLRF）、强度调谐曲线（ITC）及刺激后放电直方图（PSTH）的影响效应；并通过电刺激边缘系统核团伏隔核（NAc），考察水杨酸钠大鼠AC、MGB及IC的自反反应及听诱发反应的变化；以免疫荧光组化、Western-blot、real time-PCR方法，考察及早基因c-fos、arc/arg 3.1及脑源性神经营养因子（BDNF），NMDA受体及GABAA受体等分子标记在听脑及边缘系统的空间分布及表达量的变化，探讨电针穴位对水杨酸钠大鼠产生影响的细胞分子机制。

本研究以水杨酸钠大鼠为耳鸣模型，研究电针穴位治疗耳鸣的有效性及相关机制。采用前脉冲声惊吓抑制反射(gap prepulse inhibition acoustic startle reflex ,GPIAS)行为学研究法，结果表明电针耳区穴位听宫+翳风可改善水杨酸钠大鼠耳鸣相关行为，提示电针穴位治疗耳鸣的客观有效性。听性脑干诱发电位（auditory brainstem response，ABR）研究表明，电针穴位可改善水杨酸钠大鼠ABR，这种影响效应具有穴位特异性，电针耳区穴位听宫+翳风穴效果优于前肢穴位外关+中渚及后肢穴位足三里+三阴交。神经电生理研究表明，电针听宫+翳风可改善水杨酸钠大鼠听皮层神经元噪声及纯音阈值，电针对高频区神经元的影响具有延后性。本项目研究结果提示，电针穴位可改善耳鸣，其作用机制可能与改善听觉神经中枢功能有关。