Effect of low dosage of ciplatin on the shape and otoferlin in cochlea inner hair cells

Objective:To establish the stable and efficient hearing damage model by using low dosage of cisplatin,and investigate the mechanism.Method:C57mice were divided into 7groups(every group,n=8),the first group was the control group,the others were separately intraperitoneally injected with different dosages of cisplatin for different time.We measured the auditory brainstem response(ABR)of the mice,and obtained the basal coil of organ Corti.We observed the shape of inner hair cells(IHC)by staining AgNO3and marked otoferlin in the IHC by immunofluorescence,successively sliced by laser confocal microscopy.The RNA fragments were amplified by RT-PCR.Result:After cisplatin administration for four days,the thresholds of the ABR improved in 1.5mg/kg and 3.0mg/kg group,and compared with the control group,the ABR thresholds improved in each group with ciplatin administration for seven days.With the same dosage,the ABR threshold of the 0.75mg/kg×7dgroup was higher than 0.75mg/kg×4dgroup,and there was no time-effect relationship existing in other groups with different dosage.The otoferlin was less expressed 3.0mg/kg groups than the control group.However,the otoferlin expressed in the 1.5mg/kg groups were almost the same as the control group.The alteration of the IHC was observed most remarkablely in 3.0mg/kg×7dgroup.Conclusion:Low dosage of cisplatin can impair the hearing,and the expression of otoferlin may involve in the underlying mechanism.