Somatostatin and gentamicin-induced auditory hair cell loss.

Abstract

Hair cells of the mammalian auditory system do not regenerate, and therefore their loss leads to irreversible hearing loss. Aminoglycosides, among other substances, can irreversibly damage hair cells. Somatostatin, a peptide with hormone/neurotransmitter properties, has neuroprotective effects by binding to its receptor. In this study, we tested whether somatostatin can protect hair cells from gentamicin-induced damage in vitro. This study confirmed the expression of somatostatin receptor mRNA within the cochlea and analyzed the effect of somatostatin on gentamicin-induced hair cell damage and death in vitro. Expression of somatostatin receptor mRNA in the rat cochlea was analyzed by reverse transcriptase-polymerase chain reaction (RT-PCR). Protection of auditory hair cells from gentamicin was tested using two different concentrations (1 microM and 5 microM, respectively) of somatostatin. We detected somatostatin receptor-1 and -2 mRNA and in the organ of Corti (OC), spiral ganglion, and stria vascularis by RT-PCR. Moreover, we could see significantly less hair cell loss in the OCs that were pretreated with either 1 microM or 5 microM of somatostatin as compared with samples treated with gentamicin alone. Decreased hair cell loss in somatostatin-treated samples that had been exposed to gentamicin provides evidence for a protective effect of somatostatin in aminoglycoside-induced hair cell death in vitro.