Effects of Erlong Zuoci Pill and its disassembled prescriptions on gentamicin-induced ototoxicity model in vitro

Objective: To study the effects of Erlong Zuoci Pill (ELZCP) and its disassembled prescriptions on gentamicin (GM)-induced ototoxicity model in vitro. Methods: After 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. Results: GM 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). Conclusions: ELZCP 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.