耳迷走神经分布区穴位电刺激配合声音掩蔽法对耳鸣大鼠听性脑干反应及下丘神经递质的影响

Effects of electrical stimulation at acupoints in the distribution area of auricular vagus nerve combined with sound masking method on auditory brainstem response and neurotransmitters of inferior colliculus in rats of tinnitus

目的:探讨耳迷走神经分布区穴位电刺激配合声音掩蔽法对耳鸣大鼠听性脑干反应(ABR)和下丘神经递质γ-氨基丁酸(γ-GABA)、5-羟色胺(5-HT)、乙酰胆碱(Ach)含量的影响。方法:24只成年雄性SD大鼠随机分为对照组、模型组、7d治疗组、15d治疗组。除对照组外,其他3组大鼠每只按350mg/kg剂量腹腔注射10%水杨酸钠溶液,诱导制作耳鸣模型;对照组注射0.9%NaCl溶液。7d治疗组、15d治疗组均采取耳迷走神经分布区穴位"神门""胰""胆"电刺激配合声音掩蔽法治疗,每天1次,分别治疗7d、15d。采用TDT系统SigGenRP软件单耳给声并采集信号,检测大鼠听性脑干反应(ABR)声音阈值;酶联免疫吸附法检测并比较各组大鼠下丘γ-GABA、5-HT、Ach神经递质含量。结果:与模型组比较,7d治疗组治疗后在12k和16k频率声音刺激的ABR阈值显著下降(均P<0.05),15d治疗组,在4k至28k各频率声音刺激引出的ABR阈值均下降(P<0.05,P<0.01),且降幅大于7d治疗组。模型组γ-GABA含量低于对照组(P<0.05),15d治疗组显著高于模型组(P<0.05);模型组5-HT含量高于对照组(P<0.05),7d治疗组显著低于模型组(P<0.05),而15d治疗组则显著高于模型组(P<0.05);模型组Ach含量低于对照组(P<0.05),7d治疗组高于模型组(P<0.05)。结论:耳迷走神经电刺激配合声音掩蔽法能调节耳鸣大鼠ABR阈值,尤以15d治疗组最为显著,此作用可能与调节耳鸣大鼠下丘的γ-GABA、5-HT、Ach水平有关。

Objective To explore the effects of electrical stimulation at acupoints in the distribution area of auricular vagus nerve combined with sound masking on auditory brainstem response（ABR）and contents of neurotransmitters ofγ-aminobutyric acid（γ-GABA）,5-hydroxytryptamine（5-HT）and acetyl choline（Ach）in inferior colliculus of tinnitus rats.Methods Twenty-four male adult SD rats were randomized into a control group,a model group,a 7-d treatment group and a 15-d treatment group.Except the control group,rats in the remaining groups were treated with intraperitoneal injection of 10% salicylate sodium at a dose of 350 mg/kg to establish tinnitus model.Rats in the control group were treated with injection of 0.9% NaCl.Rats in the 7-d treatment group and 15-d treatment group were treated with electrical stimulation at＂Shenmen（TF_4）＂and＂Yidan（CO_（11））＂in the distribution area of auricular vagus nerve combined with sound masking,once a day,for 7 days and 15 days.The SigGenRP software of TDT system was applied to provide voice for single ear and collect the signal,and the voice threshold of ABR was tested.The levels ofγ-GABA,5-HT and Ach in inferior colliculus of rats were detected by enzyme linked immunosorbent assay（ELISA）and compared.Results Compared with the model group,the threshold values of ABR in 12 kHz and 16 kHz voice stimulation in the 7-d treatment group were significantly lower（all P〈0.05）;the threshold values of ABR from 4 kHz to 28 kHz voice stimulation in the 15-d treatment group were signally reduced（P〈0.05,P〈0.01）,which was more significant than those in the 7-d treatment group.The level ofγ-GABA in the model group was significantly lower than that in the control group（P〈0.05）,and that in the 15-d treatment group was apparently higher than that in the model group（P〈0.05）.The level of 5-HT in the model group was markedly higher than that in the control group（P〈0.05）,and that in the 7-d treatment group was lower than that in the model group（P〈0.05）,while that in the 15-d treatment group was apparently higher than that in the model group（P〈0.05）.The level of Ach in the model group was obviously lower than that in the control group（P〈0.05）,and that in the 7-d treatment group was higher than that in the model group（P〈0.05）.Conclusion Electrical stimulation at auricular vagus nerve combined with sound masking could regulate the threshold of ABR,especially in the 15-d treatment group.This may be ascribed to modulating the levels of neurotransmitter ofγ-GABA,5-HT and Ach in inferior colliculus.