磷霉素鼓室注射对多粘菌素B内耳毒性的保护作用

Protective effect of intratympanic injection of fosfomycin against polymycin B ototoxicity

本实验旨在探索磷霉素和多粘菌素Ｂ混合鼓室注射对耳用的影响。应用４５只豚鼠进行ＣＡＰ检测及耳蜗光镜和扫描电镜观察，结果发现两种浓度多粘菌素Ｂ均引起明显ＣＡＰ阈值升高、潜伏期延长和毛细胞的损害，随浓度增加而病变加重；当与磷霉索混合用药时，ＣＡＰ和耳蜗形态学改变较单独用多粘菌素Ｂ明显减轻，但高浓度混合液底转有部分或散在外毛细胞和内毛细胞损害。故混合液中多粘菌素Ｂ浓度不宜大高，提示临床上可试用该混合滴耳剂治疗中耳化脓性炎症。

Abstract The protective effect fosfomycin(FOM)by intratympanic injection against polymycin B(PB)ototoxicity was reported.45 guinea pigs were divided into 5 groups at random(group S was a control of sodium chloride,group Pl PB 10000 u/m1,group P2 PB 50 000u/ml,group FP1 PB 10000 u/ml+FOM 30mg,group FP2 PB 50 000 u/m +FOM 30mg).Before injection and 3,7,14 dyas after the last injection, the CAPs were measured,and the surface structures of Corit’s organ were observed under light microscope and scan-ning electronic microscope. The results showed that the changes of CAPand cochlear mor-phology were obvious in group Pl.Whereas the damages of cochlea were dramatically re-duced in group FP1.In group FP2,minor and scattered hair loss and partial deformation or confusion of stereocilia were observed in the basal turn of the cochlea. Clinically,it is possible to apply a combination of otic drops of PB and FOM in order to reduce the risk of ototoxicity in the treatment of suppurative otitis media.