Brain-derived neurotrophic factor/glial cell line-derived neurotrophic factor survival effects on auditory neurons are not limited by dexamethasone.

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 ng/ml) and in combination with each other (100 ng/ml). 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 ng/ml). In addition, dexamethasone application did not interfere with the survival-promoting effects of brain-derived neurotrophic factor or glial cell line-derived neurotrophic factor.