Protective effect of systemic administration of erythropoietin on auditory brain stem response and compound action potential thresholds in an animal model of cochlear implantation.
OBJECTIVE
An animal model of cochlear implantation has been developed, and the hearing threshold was evaluated after different surgical procedures. The effect of perioperative systemic administration of erythropoietin on the hearing loss induced by cochlear implantation was tested.


METHODS
Twenty-nine guinea pigs with normal hearing underwent implantation of a 254-microm-diameter array through a cochleostomy. The effects on hearing of cochleostomy and transient and long-term array implantation (21 days) were assessed by testing of the auditory brain stem responses and compound action potentials. Eleven implanted animals received intraperitoneal administration of erythropoietin. Selected computed tomographic scans and cochlear histologic studies were performed 1 month after implantation to confirm proper placement of the array. The erythropoietin concentration at the time of surgery was assessed in samples of perilymph, cerebrospinal fluid, and blood.


RESULTS
The cochleostomy and transient array insertion had no effect on hearing thresholds. Long-term array implantation induced a stable decrease of hearing threshold (30 dB), a decrease that was reduced by 12 dB in erythropoietin-treated animals. The erythropoietin-treated animals had better hearing preservation at higher frequencies. Fibrosis surrounding the array was seen in both groups.


CONCLUSIONS
The hearing loss observed was probably due to the presence of the array in the cochlea. The intraperitoneal injection of erythropoietin improved the hearing threshold shift induced by implantation.
Inserm UMR-S867, Minimally Invasive Robot-Based Otologic Surgery, Paris, France.
Stéphanie
S
Quesnel
Yann
Y
Nguyen
Pierre
P
Campo
Olivier
O
Hermine
Jean-Antoine
JA
Ribeil
Monique
M
Elmaleh
Alexis Bozorg
AB
Grayeli
Evelyne
E
Ferrary
Olivier
O
Sterkers
Vincent
V
Couloigner
D000200:Action Potentials; D000818:Animals; D001309:Auditory Threshold / Q000187:drug effects*; D019929:Cochlear Implantation; D004195:Disease Models, Animal; D004921:Erythropoietin / Q000008:administration & dosage*; D016057:Evoked Potentials, Auditory, Brain Stem / Q000187:drug effects*; D006168:Guinea Pigs; D034381:Hearing Loss / Q000209:etiology / Q000517:prevention & control; D007274:Injections, Intraperitoneal; D008297:Male; D016896:Treatment Outcome
D004921:Erythropoietin