Expression Patterns of Erythropoietin and Erythropoietin Receptor in the Spiral Ganglion of Guinea Pig after Noise Exposure / 대한이비인후과학회지

ABSTRACT

BACKGROUND AND OBJECTIVES: Erythropoietin (EPO) is produced in the kidney and locally in the CNS and acts through binding to erythropoietin receptor (EPO-R). Apart from playing an essential role in erythropoiesis, recent research has shown that EPO has neurotrophic and neuroprotective functions in the CNS and found EPO and EPO-R in the inner ear. The aim of this study is to investigate distribution and expression of EPO and EPO-R in the inner ear after noise exposure. MATERIALS AND METHOD: Normal guinea pigs were exposed to noise. Ten of them were sacrificed at 1 hour of the noise exposure (group B) and another 10 animals were sacrificed at day 7 (group C). Four were normal controls that were not exposed to noise (Group A). Auditory function was evaluated by ABR for 7 days. Noise-induced morphological changes of cochlea were studied by phalloidin stain. The expression of EPO and EPO-R was examined by immunofluorescence. RESULTS: The hearing threshold shift reached a level of 40 dB SPL at 8 kHz at day 1 after noise exposure and underwent a partial recovery at day 7. Increased expression of EPO and EPO-R were observed at the level of spiral ganglion cells in the noise-exposed animals. CONCLUSION: It is suggested that noise exposure affects the distribution and expression of EPO and EPO-R in the inner ear.