Protection and Regeneration of Vestibular Hair Cells—the Role of Neurotrophins after Gentamicin Ototoxicity

Abstract

The spontaneous and brain derived neurotrophic factor (BDNF) assisted recovery of vestibular hair cells in adult chinchillas following intraotic gentamicin (GM) ototoxic treatment (50 µg) was studied in three experiments. 1. GM group: One week after intraotic GM treatment all type I (100%) and most of type II hair cells (85%) were destroyed. At 4 weeks post-treatment (PT), type II hair cells experienced a significant spontaneous regeneration to 83% of normal values. 2. GM/BDNF group: Intraotic administration of 1 µg of BDNF one week after GM treatment accelerated the recovery of type II hair cells. They recovered to 81% at 2 weeks PT. The regeneration of type I hair cells reached 28% at 8 weeks PT. 3. GM&BDNF group: BDNF administered together with GM delayed the initial hair cell destruction for one week. At this time period, 23% of type I hair cells were still present, whereas the number of type II hair cells was normal. At 8 weeks PT, no type I hair cells were found, but type II hair cell numbers were normal.