水杨酸钠中耳灌注对庆大霉素耳毒性的防护作用

目的 观察水杨酸钠经中耳局部灌注给药对庆大霉素耳毒性的防护作用。方法 24只健康杂色豚鼠均接受圆窗置管术，然后随机分成3组：Ⅰ组为生理盐水对照组；Ⅱ组为庆大霉素组，腹腔注射庆大霉素，经听泡灌注生理盐水；Ⅲ组为庆大霉素加水杨酸钠组，腹腔注射庆大霉素，经听泡灌注水杨酸钠。观察各组给药前后听性脑干反应阈的变化和给药后4周毛细胞损失情况。结果 听泡置管术后ABR反应阈无明显改变；给药后2周和4周，庆大霉素组ABR反应阈较庆大霉素加水杨酸组显著增高（P〈0．01），对照组ABR反应阈无显著变化。耳蜗铺片、毛细胞计数显示庆大霉素组外毛细胞严重缺失，以底回最明显，庆大霉素加水杨酸钠组外毛细胞损失较庆大霉素组轻（P〈0．05）。对照组无明显外毛细胞缺失。结论 水杨酸钠经中耳局部给药途径可减轻庆大霉素所致听功能损害和毛细胞缺失，可在一定程度上有效预防庆大霉素的耳毒性。

Protective effects of sodium salicylate via middle ear instillation on the ototoxicity of gentamicin

Objective To investigate the protective effects of sodium salicylate via middle ear instillation on the ototoxicity of gentamicin.Methods Twenty-four healthy pigmented guinea pigs received cannula insertion via round window for middle ear instillation were randomly divided into three groups.In group I,guinea pigs were given middle ear instillation and peritoneal injection with normal saline;In group II,the animals were given peritoneal injection with gentamicin and middle ear instillation with normal saline,and in group III,peritoneal injection with gentamicin and middle ear instillation with sodium salicylate.The changes of auditory function and cochlear morphology were assessed by auditory brainstem response(ABR) testing,cochlear mapping,and hair cell accounting.Results ABR threshold measurements showed that insertion of cannula via otic vesicle did not result in significant hearing loss.Two and four weeks after drug administration,the changes of auditory threshold in group I was not obvious,but the changes were significant in group II and group III.Moreover,gentamicin induced a higher threshold shift than gentamicin combined with sodium salicylate(P<0.01).The morphologic changes of cochlea demonstrated that there were severe outer hair cell losses in group II.The!amount of outer hair cell loss in group III was less than that in group I(P<0.05),while no obvious outer hair cell loss detected in group I.Conclusion Sodium salicylate via middle ear instillation can relieve the gentamicin-induced deficits of auditory function and outer hair cell loss.The local instillation of sodium salicylate can prevent ototoxicity of aminoglycoside to some extent.