儿茶素对拟衰老大鼠耳蜗氧自由基生成的影响

Effect of Catechin on the Oxygen Free Radical in Cochlea of Aging Rats

【目的】观察儿茶素对衰老大鼠动物模型耳蜗氧自由基生成的影响,初步探讨儿茶素对听觉老化的保护效应及其机制。【方法】通过腹腔注射D-半乳糖(D-gal)建立大鼠衰老动物模型,以腹腔注射生理盐水为阴性对照组,检测其听觉脑干诱发电位(ABR)明确衰老动物听力减退情况,检测大鼠耳蜗组织丙二醛(MDA)含量和超氧化物歧化酶(SOD)活性;并观察胃内灌注儿茶素后衰老动物模型上述指标的变化。【结果】衰老模型组大鼠与对照组大鼠相比较,ABR阈值增高,耳蜗组织中MDA含量明显增高,SOD活性明显降低(P<0.05);儿茶素保护组大鼠耳蜗组织中MDA含量和SOD活性水平较对照组无变化(P>0.05),而与衰老模型组相比却逆转上述指标变化,并能提高听力(P<0.05)。【结论】氧自由基及其引发的脂质过氧化反应参与了听觉老化过程,儿茶素可能通过提高SOD活性、减少MDA生成发挥清除自由基抗氧化作用,从而改善听觉功能。

[Objective]To study the effect of catechin on the oxygen free radical in cochlea of aging rats, and to discuss its protective effect on age-related hearing loss. [Methods]The aging rat model was established by peritoneal injection of D-galactose （D-gal）, and the rats received saline injection as control. The contents of malondialdehyde （MDA） and the activities of superoxide dismutase （SOD） in the cochlea were measured. The changes of above parameters in the aging model treated with catechin were observed. [Results]In the D-galtreated rats, the content of MDA significantly increased compared with the control, whereas the activity of SOD significantly decreased（ P〈0.05）. Catechin resulted in significant decrease of MDA contents and increment of SOD activities in D-gal-induced aging model（ P〈0.05）. [Conclusion]Oxygen free radical may play roles in the age-related hearing loss. Catechin may protect aging by increasing activities of SOD and clearance of free radicals.