经圆窗膜途径局部应用L-乙酰半胱氨酸和(或)卡罗维林对新霉素耳蜗毒性的保护性作用

Round window membrane application of N-L-acetylcysteine and/or caroverine protect the cochlea against neomycin ototoxicity

目的研究经圆窗膜途径局部应用抗氧化剂L-乙酰半胱氨酸和(或)谷氨酸受体拮抗剂卡罗维林对新霉素引起的耳毒性有无保护性作用。方法40只健康豚鼠行外科手术,暴露右侧圆窗龛,将所需药物滴在明胶海绵上,再放置于圆窗龛内,分别给予0.9%生理盐水、L-乙酰半胱氨酸、卡罗维林和L-乙酰半胱氨酸+卡罗维林,30min后再滴入50%新霉素于明胶海绵上。结果与对照组相比,L-乙酰半胱氨酸组、卡罗维林组和L-乙酰半胱氨酸+卡罗维林组平均听阈分别改善27、28和37dB,差异均有显著性(P<0.01);对照组的平均外毛细胞损失率为85%,平均内毛细胞损失率为81%;与其相比,L-乙酰半胱氨酸组、卡罗维林组和L-乙酰半胱氨酸+卡罗维林组的平均外毛细胞损失率分别为56%、60%和40%,平均内毛细胞损失率分别为60%、57%和37%,差异均有显著性(P<0.01)。结论经圆窗膜途径局部应用L-乙酰半胱氨酸和(或)卡罗维林能够保护新霉素引起的耳毒性。

Objeclive To test whether antioxidant N-L-acetylcysteine and/or glutamate receptor antagonist caroverine could successfully protect the cochlea from neomycin-induced ototoxicity by using round window membrane locally. Methods 40 healthy guinea pigs were undergone operation to exposure the fight round window niche. Then, the drugs were dropped onto gelfoam then the gelfoam was placed onto the round window niche, the animals were administrated： normal saline, N-L-acetylcysteine, caroverineand N-L-acetylcysteineplus caroverine respectivly and 50% neomycin was dropped into gelfoam after 30 minutes. Results Comparing experment group with the control group, the average threshold of the N-L-acetylcysteine （NAC） group, the caroverine（Car） group＂ and the NAC ＋ Car group were ameliorated 27 dB ,28 dB and 37 dB respectively, the difference was significant （P 〈0. 01 ）between the control and all tested groups. The mean outer hair cell （OHC） loss rate of the control group was 85 % and mean inner hair cell（IHC） loss rate was 81% ; The mean OHC loss rate of the NAC group, the Car group and the NAC ＋ Car group was 56% ,60% and 40% , and The mean IHC loss rate of them were 60% ,57% and 37% respectively, the difference was significant（ P 〈0. 01 ）between the control group and all test groups. Conclusion Local RWM application of NAC and/or Car can protect cochlea from neomycin-induced ototoxicity.