甲状腺功能低下对ABR和DPOAE的影响

The Effect of Experimental Hypothyroidism on ABR and DPOAE

为了探讨甲状腺功能低下（甲低）时听觉功能损害的部位及可能的致病机理，用含甲硫咪唑（０．１５ｇ／Ｌ）的饮用水喂养大鼠制造甲低模型，对甲低前后的大鼠进行听性脑干反应（ＡＢＲ）和畸变产物耳声发射（ＤＰＯＡＥ）的检测。结果发现：甲低后ＡＢＲ阈值明显升高；而ＡＢＲ各波潜伏期及波间期无明显变化。ＤＰＯＡＥ“听力图”显示甲低后ＤＰＯＡＥ振幅明显下降；ＤＰＯＡＥ阈值明显上升。提示耳蜗是甲低时听觉功能损害的主要部位，文中对可能的发病机理进行了讨论。

In order to investigate the site of lesion and putative pathogenesis of auditory impairment in hypothyroidism,experiments were designed to study the effect of phypothyroidism on the auditory brain stem response(ABR) and distortion production otoacoustic emission(DPOAE) in two month old Spraque Dawley rats.The rats were made hypothyroid by the use of methimazole(0.15 g/L) in their drinking water for six months.The ABR thresholds increase significantly following hypothyroidism,but neither absolute latencies of wave I,III,V nor interpeak latencies I～III,III～V,I～V are found to change following hypothyroidism.The DPOAE audiogram shows that there is a significant reduction in DPOAE amplitudes and the DPOAE detection thresholds increase significantly in hypothyroid rats,which is in agreement with the ABR thresholds alteration.The results showed that cochlea may be the main site of lesion of auditory impairmant in hypothyroidism.The putative pathogenesis was discussed.