Ototoxicity on cochlear nucleus neurons following systemic application of gentamicin.
CONCLUSIONS
The gentamicin-induced pathological alteration in the cochlear nucleus is not exclusively a secondary consequence of the damage in the cochlea. Instead, the toxic effect of gentamicin on the cochlear nucleus may occur simultaneously or even earlier than that on the cochlea.


OBJECTIVE
To investigate the pathological alteration of cochlear nucleus neurons in guinea pigs following systemic application of gentamicin.


METHODS
Guinea pigs were injected with gentamicin for 1 day, 3 days, 1 week, 2 weeks, and 3 weeks, respectively. In gentamicin-treated animals, the hearing function was evaluated by measuring the auditory brainstem response (ABR). The number and cross-sectional area of substance P-positive neurons in the cochlear nucleus were also measured.


RESULTS
The threshold of ABR and the number of substance P-positive neurons in the cochlear nucleus were significantly increased after 1 week and 3 days of injection of gentamicin, respectively. The cross-sectional area of substance P-positive neurons in the cochlear nucleus was significantly reduced after 1-day injection of gentamicin.
Department of Otorhinolaryngology, 2nd affiliated Hospital of Xi'an, ShanXi, PR China.
Min
M
Xu
Hai-Tao
HT
Hu
Zhe
Z
Jin
Gang
G
Chen
Wei-Xi
WX
Wang
Yu-Lin
YL
Fan
Matti
M
Anniko
Maoli
M
Duan
D000818:Animals; D000900:Anti-Bacterial Agents / Q000633:toxicity*; D001309:Auditory Threshold / Q000187:drug effects; D002452:Cell Count; D048429:Cell Size / Q000187:drug effects; D017626:Cochlear Nucleus / Q000187:drug effects* / Q000473:pathology; D004334:Drug Administration Schedule; D016057:Evoked Potentials, Auditory, Brain Stem / Q000187:drug effects; D005839:Gentamicins / Q000633:toxicity*; D006168:Guinea Pigs; D007124:Immunoenzyme Techniques; D007274:Injections, Intraperitoneal; D009474:Neurons / Q000187:drug effects / Q000473:pathology; D013373:Substance P / Q000378:metabolism
D000900:Anti-Bacterial Agents; D005839:Gentamicins; D013373:Substance P