豚鼠肌注庆大霉素10天和17天畸变产物耳声发射特性研究

Research on DPOAE of Guinea Pigs Treated with Gentamicin

研究豚鼠肌注庆大霉素(GM)10和17 d耳声发射DP-gram和I/O曲线的特征性改变。选用健康豚鼠40只,随机分为4组:I组肌注GM 10 d,II组肌注等容量生理盐水10 d,III组肌注GM 17 d,IV组肌注等容量生理盐水17 d;采用CELESTA 503型耳声发射测试分析系统,观测四组豚鼠DP-gram和I/O曲线特征性改变,计数耳蜗外毛细胞缺失率。(1)I组DP-gram在4、6和8 kHz处DPOAE(Distortion product otoacoustic emission)幅值明显下降,同II组相比有显著性差异(t为2.52、1.92、2.10,P<0.05)。III组DP-gram在3、4、6和8 kHz处明显下降,同IV组相比有显著性差异(t为3.27、2.81、2.92、3.13,P<0.01)。I、III组I/O曲线在不同频率不同刺激强度下DPOAE幅值明显下降。(2)刺激强度L1<60 dB SPL,I、III组I/O曲线在4、6和8 kHz引起DPOAE反应幅值为0 dB时最小刺激强度较相应对照组大。(3)II、II组在8 kHz阈移均数分别为5.0±3.8 dB和25±6.2 dB。(4)I、III组外毛细胞缺失率分别为22.16%和48.36%,同相应对照组相比有显著性差异(P<0.01)。豚鼠肌注庆大霉素10 d和17 d,畸变产物耳声发射频率特异性好,DPOAE的改变与耳蜗形态学变化一致,DPOAE可以作为监测庆大霉素耳毒性敏感指标。

This study was designed to disclose the specific changes of distortion product otoacoustic emission （DPOAE）, including DP-gram and I/O -gram in guinea pigs treated with GM for 10 and 17 days. Forty guinea pigs were divided into four groups：groupⅠ （treated with GM for 10 days）, group Ⅱ （treated with normal saline for 10 days） ,group Ⅲ （treated with GM for 17 days）, group Ⅳ （treated with normal saline for 17 days）. DPOAE including DP-gram and DP-I/O was recorded by use of CELESTA 503 Cochlear Emission Analysis and the out hair cell loss was numerated. （ 1 ） The amplitude in group Ⅰ showed significant reduction at frequencies of 4, 6, 8 kHz. There were significant differences, oompared to group II （t = 2.52,1.92,2.10, P 〈 0.05）. The amplitude in group Ⅲ also decreased at frequencies of 3, 4, 6, 8 kHz. There were also significant differences omapared to group Ⅳ （ t = 3.27,2.81,2.92,3.13, P 〈 0.01 ）. The amplitude of DP-I/O in group Ⅰ and group Ⅲ at different frequencies and stimulus levels showed reduction. （2）At the level L1 〈60 dB SPL, the stimulus levels to elicit a 0 dB response in group Ⅰ and group Ⅲ were higher than these in corresponding control groups, respectively. （3（ The mean of threshold shift was 5.0±3.8 dB in group Ⅰ and 25.0±6 dB in group Ⅲ at 8 kHz frequency. （4）The out hair cell loss was 22.16% in group Ⅰ and 48.36% in group Ⅲ,both showed significant difference as compared to controls,respectively （P〈0.01）. The employment of DPOAE can be a useful tool in monitoring ototoxicity of GM for its sensitivity and specificity in guinea pigs treated with GM. The changes in DPOAE were consistent with these in histology.