噪声对豚鼠耳蜗抗氧化酶防御体系的影响

Effects of noise on antioxidant enzymes of cochlea in guinea pigs

目的 了解噪声对耳蜗抗氧化酶防御体系的影响。方法 雄性花色豚鼠 1 6只 ,体重2 50～ 30 0g,随机分为 2组 ,正常对照组和噪声暴露组 ,每组 8只。噪声暴露组接触中心频率为 4kHz的倍频程连续噪声 ,强度为 1 0 0dB(SPL) ,每天 8h ,连续 3d。于接触噪声前、噪声暴露结束后即刻测定听觉诱发脑干反应 (ABR) ,并测定活性氧 (ROS)水平和超氧化物歧化酶 (SOD)、过氧化氢酶 (CAT)、谷胱甘肽过氧化物酶 (GSH Px)活力。结果 噪声暴露组的ROS水平为 (2 81 .2± 3 .5)U/mgpro ,正常对照组为 (2 73 .0± 3 .2 )U/mgpro,差异有显著性 (P <0 .0 5) ,SOD、CAT及GSH Px活力分别为 (2 0 6 .5±5 .1 )NU/mgpro、(47.0± 9.0 )U/gpro、(1 4 .1± 2 .5)U/mgpro,比正常对照组 [分别为 (2 2 1 .8± 4 .8)NU/mgpro、(60 .8± 9.9)U/gpro、(2 1 .1± 3 .1 )U/mgpro]明显降低 ,且差异有显著性 (P <0 .0 5)。

Objective To investigate the effect of noise on the antioxidant enzymes of cochleae. Methods 16 male pigmented guinea pigs(250～300 g) were randomly divided into 2 groups,control group and noise group.Each group had 8 animals.The animals in noise group were performed auditory evoked brainstem responses(ABR) recording before and after exposure to a continuous noise(4 kHz,octave band,100 dB,SPL) 8 h/d for 3 consecutive days.Immediately at the end of the third day's noise exposure after ABR recording,guinea pigs were decapitated.Both the right and the left cochlea with the bony capsule removed were homogenized,and the supernatants were prepared for assays.Reactive oxygen species(ROS),superoxide dismutase(SOD),catalase(CAT) and glutathione peroxidase(GSH Px) were measured. Results ROS level of the noise group[(281.2±3.5)U/mg pro] was significantly higher than that of the control group[(273.0±3.2)U/mg pro, P <0.05] and SOD,CAT and GSH Px activities of the noise group[(206.5±5.1)NU/mg pro,(47.0±9.0) U/g pro, (14.1±2.5)U/mg pro respectively] were significantly lower than that of the control group[(221.8±4.8)NU/mg pro,(60.8±9.9)U/g pro,(21.1±3.1)U/mg pro respectively, P <0.05]. Conclusion Noise may damage the defensive system of antioxidant enzymes in cochlea.