不同品系正常成年小鼠听性脑干反应特点

目的 研究正常成年CBA、C57BL、昆明系和129系四种品系小鼠的听性脑干反应(auditory brainstem response,ABR),分析其ABR反应阈和潜伏期,得到正常值范围,标准化测试流程,为小鼠的听觉相关研究提供参考.方法 对6周龄正常CBA、C57BL、昆明系和129系四种品系小鼠各20只(20耳),完全麻醉后,进行短声(click)和短纯音(tone burst,tb) ABR测试,观察四种品系小鼠ABR各波的引出率,记录引出率最高的波反应阈值及各波潜伏期.结果 ①在80 dB SPL强度下,CBA、C57BL、昆明系和129系四种品系小鼠ABR各波引出率均为100％,CBA小鼠ABR波形分化最好;在30 dB SPL强度下,除129小鼠外,其余3种小鼠波Ⅱ引出率最高,129小鼠在阈值附近50 dB SPL强度下也是波Ⅱ引出率最高;129小鼠ABR反应阈明显高于其它三种小鼠,差异均有统计学意义(P均＜0.05);②四种品系小鼠的短纯音听觉敏感频率为8、12、16 kHz,其中对12 kHz的短纯音最敏感;③麻醉情况下,ABR各波潜伏期随着测试时间延长而延长,尤其波Ⅲ以后各波潜伏期延长更明显.80 dB SPL强度下CBA、C57BL、昆明系、129系四种小鼠ABR波形在波工前均可分化出SP(summating potential,SP)波,引出率分别为100％、90％、80％、50％,相同刺激条件下,SP波出现率高的小鼠其ABR反应阈相对较低.结论 麻醉状态下,CBA、C57BL、昆明系和129系四种品系小鼠短声及短纯音ABR波Ⅱ引出率最高,故以波Ⅱ刚刚出现的刺激声强度确定为反应阈值;C57BL、昆明系和129系三种品系小鼠的ABR结果均没有CBA小鼠稳定,四种品系小鼠中CBA小鼠更适合用来建立听觉功能相关研究的动物模型;SP波可间接反映毛细胞功能.

The Auditory Brainstem Response in Normal Adult Mice of Different Strains

Objective To study the auditory brainstem response (ABR) of normal adult CBA,C57BL,Kunming and 129 mice and analyze the ABR thresholds and latencies in order to obtain normal values and standardized testing process,thereby providing important reference for future auditory hearing research in mouse.Methods Six -week-old normal mice of CBA,C57BL,Kunming and 129(each strain containing 20 ears of 20 mice) were used in this study.ABR test with both the click and tone burst were carried on.The incidence of each wave and the thresholds and latencies of various strains of mice were recorded.Results For these four strains of mice,wave Ⅱ had the highest occurrence rate and was used to determine the thresholds.Four strains of mice all were sensitive to the sound at 8,12,16 kHz,most to 12 kHz.Under anesthesia condition,the latency of each ABR wave prolonged as testing time increase,especially the waves Ⅲ ～ V which reflected the functions of the part near the cerebral center.Conclusion Under anesthesia state,for these four strains of mice,wave Ⅱ has the highest occurrence rate and is used to determine the threshold.We determine the intensity level at which Wave Ⅱ just appeared as the ABR threshold.The stain of CBA mice is the best one to establish an animal model related to hearing function research because ABR of the other three strains are not stable as the CBA mice.Wave SP can reflect the hair cell functions indirectly.