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Artemin and its receptors are upregulated in the auditory nerve of deafened rats as a possible intrinsic protective mechanism against ototoxicity-related apoptosis. Consequently, we examined the effect of artemin on spiral ganglion neurons in vitroand in vivo. Spiral ganglion neurons were isolated from neonatal rats and cultured in serum-free medium supplemented with artemin andor brain-derived neurotrophic factor (BDNF). In vitro, the survival rate of spiral ganglion neurons cultivated with artemin or BDNF was significantly improved compared with negative controls. In addition, artemin was delivered to the inner ear of deafened guinea pigs for 28 days. In-vivo artemin was as effective as BDNF in spiral ganglion neuron protection. Therefore, artemin promotes the survival of spiral ganglion neurons in vitroand in vivo.

Cochlear implant performance depends on the number of surviving excitable auditory neurons and prevention of degradation of nerve–electrode interaction caused by adverse tissue reactions. Glucocorticoids and neurotrophic factors are promising options for a possible therapeutic intervention. Neurons dissociated from the spiral ganglion of rats (3–5 days old) were cultivated with addition of brain-derived neurotrophic factor, glial cell line-derived neurotrophic factor and the corticosteroid dexamethasone in various concentrations (25, 50, 100 ngml) and in combination with each other (100 ngml). The results suggest that a combination of brain-derived neurotrophic factor and glial cell line-derived neurotrophic factor does not enhance spiral ganglion cell survival significantly when compared with single brain-derived neurotrophic factor treatment (100 ngml). In addition, dexamethasone application did not interfere with the survival-promoting effects of brain-derived neurotrophic factor or glial cell line-derived neurotrophic factor.