OBJECTIVETo study the effects of Erlong Zuoci Pill (, ELZCP) and its disassembled: prescriptions on gentamicin (GM)-induced ototoxicity model in vitro.

METHODSAfter the spiral organ of cochleae: of newborn mice (postnatal days: 2-3) cultured for 24 h, GM alone or combined with water extracting-alcohol precipitating solution of ELZCP or with its disassembled prescriptions was added. Hair cells were observed under a fluorescence microscope after TRITC-phalloidin staining, and the cochlear hair cell loss rate was calculated by counting the whole cochlear hair cells and analyzed by whole cochlear hair cells analyzing software.

RESULTSGM induced cochlear outer hair cells (OHCs) and inner hair cells (IHCs) injuries in a dose-dependent manner, and they were significantly different as compared with those in the normal control group (P<0.05, P<0.01). ELZCP at the concentration of 0.003-3 mg/mL could decrease the hair cells loss induced by the 0.3 mmol/L GM (P<0.05, P<0.01), the effects was in a dose-dependent manner, and the concentration of 0.3 mg/mL showed the optimal protective effect. For the ELZCP disassembled prescriptions, Liuwei-Dihuang could decrease OHC loss rate than that in the 0.3 mmol/L GM model group (P<0.05), but the OHC loss rate was still higher than that in the ELZCP group (P<0.01), which indicated that the protective effect of hair cells by Liuwei-Dihuang was not better than that of ELZCP. Poria decreased OHC loss rate from 72.1 % +/-3.7 % to 58.8 %+/- 8.2 % (P<0.05).

CONCLUSIONSELZCP could play a role in antagonizing the injury of cochlear hair cells induced by GM ototoxicity,: and its disassembled prescriptions, Liuwei-Dihuang was the main component to protect the cochlear hair cells from GM-induced ototoxicity, and Magnetitum combined with Radix Bupleurui could strengthen the action of the whole prescription; Poria could reduce GM-induced OHC loss.