EGb761减轻大鼠内耳血管纹损伤的实验研究

Protective effects of Ginkgo biloba extract on cochlear stria vascularis in rats

目的观察大鼠噪声暴露后其耳蜗电生理与血管纹细胞超微结构的改变,探讨使用银杏叶提取物(EGb761)后减轻血管纹损伤的保护作用的机制。方法实验组大鼠噪声暴露后腹腔注射EGb761,对照组动物噪声暴露后注射等量生理盐水,于处理前后对两组的听力及透射电镜所见耳蜗血管纹结构加以比较。生化检测耳蜗血管纹组织超氧化物歧化酶(superoxide dimutase,SOD)活性及丙二醛(malondialdehyde,MDA)含量。结果实验组的听力损失明显小于对照组(P<0.05);耳蜗透射电镜观察发现,对照组血管纹边缘细胞核周间隙明显增宽,核异染色质明显边集,线粒体水肿,嵴断裂或消失,部分空泡化。实验组耳蜗细胞损伤明显轻于对照组。两组SOD、MDA检测差异有显著性。结论大鼠噪声暴露后应用EGb761能降低ABR阈移,其机制可能是清除氧自由基,保护血管纹细胞,从而减轻噪声性耳蜗损伤。

Objective To study potential protective effects of Ginkgo biloba extract （EGb761） on cochlear stria vascularis against noise-induced damage. Methods Twenty rats were randomly divided into a noise exposure only group （n=10） and EGb treamment group （n=10）. The animals received noise at 110 dB SPL, 6 hours/day for 10 consecutive days. Animals in the treatment group received EGb761 injection （10ml/day） while those in the control group received 0.9% saline of the same volume. Auditory brainsterm responses （ABR） were tested before and after noise exposure. The stria vascularis tissue was examined under a tranismision electron microscpoe （TEM）. The amount of malondiadehyde （MDA） and activity of superoxide dismutase （SOD） were also measured. Results ABRs suggested less hearing impairment in the treatment group than the noise exposure only group. Cellular damage was also less in, EGb761-treated animals than in the control animals, with lower amount of MDA and increased SOD activity, Conclusion EGb761 appears to play a moderate preteetive role in the stria vascularis against noise-induced damage, probably through increasing SOD supply and inhibiting oxidation pathway.