亚氨乙基赖氨酸拮抗噪声损伤豚鼠听力的实验研究

目的　探讨亚氨乙基赖氨酸对豚鼠噪声性损伤的拮抗作用。方法　选健康白色红目豚鼠 4 0只 ,随机分为 4组 :A组为正常对照组 ,B组为噪声组 ,C组为噪声 +药物组 ,D组为亚氨乙基赖氨酸组。B、C组豚鼠暴露于 115dB白噪声连续 6d ,每天连续 6h ;C组豚鼠每天腹腔注射亚氨乙基赖氨酸 10mg/kg ,B组豚鼠腹腔注射等量的生理盐水 ,D组豚鼠每天腹腔注射亚氨乙基赖氨酸 10mg/kg,并不暴露于噪声。各组豚鼠在实验前、后均行ABR听阈检测。用免疫组化方法检测诱生型一氧化氮合成酶 (NOSⅡ )在各组豚鼠耳蜗的表达。各组豚鼠耳蜗行扫描电镜检查。观察比较各组豚鼠ABR听阈、NOSⅡ染色强弱及耳蜗形态。结果　实验前 ,A、B、C、D各组间ABR听阈的差异无显著性 (P >0 .0 5 )。实验后 ,A组、D组ABR听阈无明显改变 ,而B组和C组ABR听阈则有明显改变 ,B组ABR听阈为 (6 0 .2 3± 11.2 3)dB ,C组为 (38.4 6± 7.2 4 )dB ,两组比较 ,差异有显著性 (P <0 .0 5 )。NOSⅡ在A、D组耳蜗表达阴性 ,B组耳蜗表达较强 ,C组耳蜗表达较弱。B组豚鼠耳蜗外毛细胞损伤较C组重。结论　NOSⅡ在噪声所致豚鼠耳蜗损伤中呈阳性表达 ,亚氨乙基赖氨酸能抑制NOSⅡ的活力 ,且对噪声所致豚鼠耳蜗损伤有拮抗作用 ,表明一氧化氮在噪声性聋的发病中起重要作用。

The experimental study of the anti-damage effect of irminoethyl-lysine on noise-induced cochlea damage in guinea pig

OBJECTIVE: To investigate the anti-damage effect of iminoethyl-lysine on noise-induced cochlea damage in guinea pig. METHODS: 40 healthy red eye guinea pigs were randomly divided into 4 groups: Group A, normal control group; Group B, noise group; Group C, noise and drug group; Group D, iminoethyl-lysine group. Guinea pigs of both group B and group C were exposed to 115 dB white noise for 6 hours/day for 6 days. Group C and Group D were treated with iminoethyl-lysine(10 mg/kg) intraperitoneally, while Group B were treated with the same volume of physiological saline. ABR hearing threshold was measured in all animals before and after experiment. The expression of inducible nitric oxide synthase(NOS II) in the cochlea was examined by the method of immunohistochemistry. Also the cochlea of four groups were examined with scanning electronic microscope. ABR hearing threshold, expression of NOS II and structure of cochlea of four groups were compared with each other. RESULTS: There was no significant difference in ABR hearing threshold among four groups before the experiment(P > 0.05). There was no significant ABR hearing threshold shift in Group A and Group D after the experiment(P > 0.05), and there was significant ABR hearing threshold shift in Group B and Group C(P < 0.05). After the experiment, the ABR hearing threshold of group B(60.23 +/- 11.23) dB, was higher than that of Group C(38.46 +/- 7.24) dB, P < 0.05. The expression of NOS II was negative in the cochlea of Group A and Group D, but was stronger in Group B than that in Group C. The damage of outer hair cells of cochlea of Group B was more severe than that of Group C. CONCLUSIONS: The expression of NOS II in the guinea pig's cochlea damaged by noise is positive. Iminoethyl-lysine could inhibit the activity of NOS II and has the anti-damage effect on noise-induced cochlea damage. It is indicated that nitric oxide plays an important role in the pathogenesis of noise-induced hearing loss.