银杏叶提取物对噪声致大鼠螺旋神经节损伤的保护作用

An Experimental Study on the Protective Effects of Ginkgo Biloba Extract on the Spiral Ganglion Neuron of the Rat Cochlea

目的探讨银杏叶提取物对大鼠噪声暴露后螺旋神经节损伤的保护作用。方法将36只SD大鼠分为三组:正常对照组(正常组)、生理盐水+噪声暴露组(噪声组)、银杏叶提取物+噪声暴露组(用药组),每组12只。后两组大鼠每天暴露于110dBSPL白噪声中6h,连续10天,且于噪声暴露开始每天分别腹腔注射生理盐水和银杏叶提取物10ml/d。所有大鼠均于实验前和实验第10天检测听性脑干反应(auditory brainstem response,ABR),并于第二次测试ABR后处死动物,检测耳蜗组织超氧化物歧化酶(SOD)活性、丙二醛(MDA)含量,并用透射电镜观察耳蜗螺旋神经节细胞的超微结构变化。结果实验后噪声组和用药组的ABR阈值均高于正常组,但用药组显著低于噪声组,差异有统计学意义;用药组SOD活性较噪声组明显增加、MDA含量较噪声组显著降低,差异有统计学意义;用药组耳蜗螺旋神经节损害明显轻于噪声组。结论银杏叶提取物对大鼠噪声暴露后螺旋神经节细胞的损害具有保护作用。

Objective To investigate the protective effects of the extract of ginkgo biloba （EGb） on the spiral ganglion neuron（SGNs） in cochlea tissues on the hearing loss induced by noise in rats.Methods Thirty-six healthy animals were randomly divided into three groups ：the normal control group （n=12）,the noise exposured group（n=12） and the EGb treamment group （n=12）. The control group received no noise and no medications. The other two groups were exposed to the noise of 110 dB SPL for consecutively 10 days,6 hours per day. The treatment group rats were injected with 10 ml/d EGb while the other two groups with 0.9% saline of the same amount. The experiment lasted for ten days. The rats were measured by auditory brainsterm response （ABR） before and after niose exposure. The ultrastructural changes of SGNs were detected by tranismision electron microscpoe （TEM） and the contents of malondiadehyde （MDA） and activities of superoxide dismutase （SOD） were also measured.Results Hearing were signifcantlly decreased in the experimental group. Nevertheless,EGb relatively reduced the contents of MDA while increased the activities of SOD.Conclusion EGb seems to be able to moderately pretect SGNs and to play a preventive and remedial role in noise-induced hearing loss.