耳鸣动物行为学模型的制作

Fabrication of a Behavioral Animal Model of Tinnitus

目的 建立食物抑制法耳鸣动物模型,为耳鸣研究提供一种客观手段。方法 雄性健康wistar大鼠30只,随机平均分成6组。第1、2组为水杨酸钠组,皮下注射水杨酸钠(salicylic acid缩写为SA),每日350mg/kg体重;第3、4组为生理盐水组;第5、6组为尼莫地平组,注射水杨酸钠后再皮下注射尼莫地平每日1mg/kg体重。在隔声室一周的适应期内,只在夜间给动物投放食物,进入实验期开始禁食。将禁食后非常饥饿的动物置于另一隔声室内进行条件反射训练。训练只在夜晚进行。实验期间动物所处的两个隔声室持续给予背景白噪声,强度为55dB(SPL)。第1、3、5组从条件反射建立前开始给药。训练时给动物供食并记录摄食次数。背景噪声停止为条件刺激,电击为非条件刺激。经强化训练后形成“背景噪声停止-摄食减少或停止”的条件反射。第2、4、6组在条件反射建立后开始给药。最后,所有动物不再给予电击,观察条件反射的消退期时间,以判断动物是否产生耳鸣。结果 各组动物的消退时间经方差分析显示具有显著性意义。说明大鼠注射水杨酸钠后有耳鸣产生,尼莫地平能够消除水杨酸钠诱发的耳鸣。动物夜间训练兴奋性良好,造模成功率达到96.7％。结论 食物抑制法耳鸣动物模型证实水杨酸钠造成动物产生耳鸣的存在。本实验方法切实可行,可重复性良好。

Objective To found a food suppression of animal model of tinnitus and present objective method for tinnitus research. Method Adult 1 and 2 were injected with SA 350 mg/kg, normal saline was administrated to animals in Group 3 and 4 and animals in Group 5 and 6 were received Nimodipine (1mg/kg) injection. Subjects had to hear a persistent white background noise 55 dB (SPL). A food diet was given to all subjects, and then subjects began to have a conditioned training in sound-proof room. Medicine was given to all animals in Group 1, 3 and 5 before conditioned reflex. The background noise offset was the conditioned stimulus and the foot shock was the unconditioned stimulus. Hungry subjects were permitted to press for food during daily training session. The number of pressing was recorded automatically at the same time. After three or four days' training, subjects learnt rapidly to associate noise offset with shock, so subjects were established a behavioral conditioned reflex. Animals in Group 2, 4 and 6 began to have medicine after conditioned reflex. Terrified by the shock, subjects decreased or stopped pressing for food with the presentation of conditioned stimulus. But gradually subjects forgot the fear of shock without any shock present in next sessions. The vanished time was written down in order to decide whether subjects hear the tinnitus or not. Result There were significant differences among all groups and all training days (test, P<0. 05). Subjects heard the tinnitus after SA injecting and Nimodipine can cure the tinnitus induced by SA. Conclusion Food suppression of animal model of tinnitus can suggest the presence of subjects' feeling of tinnitus induced by SA.