In vivo protection of spiral ganglion neurons by bryostatin 1: preliminary results

Background: We aim to demonstrate the effect of bryostatin 1, a macrocyclic lactone that activates protein kinase C, on spiral ganglion neurons (SGNs) of adult guinea pigs deafened by aminoglycoside. Methodology: Twenty-one guinea pigs were deafened by the aminoglycoside gentamicin and then treated by continuous infusion of experimental molecule for 1 month. The experimental molecule was bryostatin 1, artificial perilymph (negative control), or neurotrophins and an apoptosis inhibitor (positive control). Neuronal density in the spiral ganglia was quantified. Results: Bryostatin 1 protected SGNs after a gentamicin challenge. Conclusions: Bryostatin 1 has a neuroprotective effect when administered continuously at low doses in adult guinea pigs.