Growth factor interactions in cultures of dissociated adult acoustic ganglia: neuronotrophic effects.

Auditory neurons cultured from adult rat acoustic ganglia require for survival either a substrate bound factor(s) present in astrocyte conditioned medium or substrate bound basic fibroblast growth factor (bFGF). Nerve growth factor (NGF) is not a survival factor for these neurons in vitro, but when used in combination with substrate bound bFGF, NGF does vigorously stimulate a neuritogenesis response by these neurons. Transforming growth factor beta (TGF beta 1) enhances the survival effect that bFGF has on these adult auditory neurons but does not by itself promote their survival in dissociated acoustic ganglion cultures. We propose that there may be complex interactions and synergy exerted by these growth factors (i.e. bFGF, NGF, TGF beta 1) during injury to the inner ear.