Otoprotective effects of erythropoietin on Cdh23erl/erl mice

Abstract

The Cdh23erl/erl mice are a novel mouse model for DFNB12 and are characterized by progressive hearing loss. In this study, erythropoietin (EPO) was given to the Cdh23erl/erl mice by intraperitoneal injection every other day from P7 for 7weeks. Phosphate-buffered saline-treated or untreated Cdh23erl/erl mice were used as controls. Auditory-evoked brainstem response (ABR) thresholds and distortion product oto-acoustic emission (DPOAE) were measured in the mouse groups at the age of 4, 6 and 8weeks. The results show that EPO can significantly decrease the ABR thresholds in the Cdh23erl/erl mice as compared with those of the untreated mice at stimulus frequencies of click, 8-, 16- and 32-kHz at three time points. Meanwhile, DPOAE amplitudes in the EPO-treated Cdh23erl/erl mouse group were significantly higher than those of the untreated groups at f2 frequency of 15383Hz at the three time points. Furthermore, the mean percentage of outer hair cell loss at middle through basal turns of cochleae was significantly lower in EPO-treated Cdh23erl/erl mice than in the untreated mice (P<0.05). This is the first report that EPO acts as an otoprotectant in a DFNB12 mouse model with progressive hearing loss.