连翘酯苷对顺铂耳毒性防护作用的实验研究

Investigation on the Protective Effects of Forsythiaside Against Cisplatin-Induced Ototoxicity in Guinea Pigs

目的观察连翘酯苷对顺铂耳毒性的防护作用并探讨其机制。方法将42只听力正常豚鼠随机分为空白组(10只):腹腔注射生理盐水8.0 ml·kg-1·d-1,连续8天;顺铂组(16只):腹腔注射顺铂2.0 mg·kg-1·d-1,连续8天;拮抗组(16只):前2天腹腔注射连翘酯苷25.0 mg·kg-1·d-1,第3天起腹腔注射连翘酯苷后30 min,再腹腔注射顺铂2.0 mg·kg-1·d-1,连续8天。每组豚鼠首次用药前及末次用药后第二天均行ABR检测,末次检测完毕后,心脏穿刺采血检测血清总超氧化物歧化酶(total superoxide disumutase,T-SOD)活性和丙二醛(malondialdehyde,MDA)含量,最后断头处死并取耳蜗,行硝酸银染色全耳蜗铺片、耳蜗组织切片和扫描电镜观察。结果空白组、顺铂组、拮抗组用药后ABR阈值分别为7.57±4.59、41.65±6.56、30.63±5.02 dB nHL;血清T-SOD活性分别为186.18±23.46、82.61±36.12、123.53±30.76 U/ml;MDA含量分别为4.14±0.79、10.69±1.21、7.85±0.97 nmol/ml。拮抗组ABR阈值低于顺铂组(P<0.05),顺铂组血清中T-SOD活性最低,而MDA含量最高,差异有统计学意义(P<0.5)。顺铂组耳蜗外毛细胞缺失明显,平均缺失率为53.42%,毛细胞结构紊乱,血管纹紊乱、螺旋神经节细胞数减少,而拮抗组这些损害明显减轻。结论连翘酯苷在一定程度上可以防护顺铂所致的耳蜗损伤,机制可能与其清除耳蜗组织氧自由基、减少氧化应激反应有关。

Objective To study the protective effect and its mechanism of forsythiaside on cisplatin-induced ototoxicity.Methods 42 guinea pigs with normal hearing were randomly divided into 3 groups.The first group（control group,n=10） received 8.0 ml/kg-1·d-1 physiologic saline by intraperitoneal（i.p.） injection for 8 days.The second group（cisplatin group,n=16） was treated with cisplatin（2 mg/kg per day,i.p.injection） for 8 days.The third group（forsythiaside group,n=16） was given forsythiaside（25 mg/kg per day,i.p.injection） only for 2 days and then was given forsythiaside（25 mg/kg per day,i.p.injection） and cisplatin（2 mg/kg per day,i.p.injection） for 8 days.Each animal was tested with auditory brainstem response（ABR） before injection and after the second day of the corresponding treatment,and the animal was executed after the final recording session.The structures of cochlea were observed by light microscope and scanning electron microscope,the content of malondialdehyde（MDA） and total serum superoxide dismutase（T-SOD） activity were also tested.Results After cisplatin injection,the ABR threshold was significantly increased in cisplatin group,and the outer hair cells,stria vascularis and spiral ganglion cells（SGCs） were severely damaged.In addition,significant increase of MDA and decrease of T-SOD activity were also detected in the serum.In contrast to the cisplafin group,added with forsythiaside,the ABR threshold was significantly declined and the damage on the outer hair cells,stria vascularis and spiral ganglion cells（SGCs） were significantly alleviated.Conclusion Forsythiaside can significantly reduce the cisplatin-induced side effects and this may be related to anti-free radicals.