Salicylate initiates apoptosis in the spiral ganglion neuron of guinea pig cochlea by activating caspase-3.
Neurochem Res
; 36(6): 1108-15, 2011 Jun.
Article
em En
| MEDLINE
| ID: mdl-21451968
ABSTRACT
Salicylate-induced ototoxicity leading to sensorineural hearing loss (SNHL) and tinnitus is well documented. However, the exact mechanisms are poorly defined. Caspase-3 is a member of the class of effector caspases and has been activated in nearly every model of apoptosis. To examine its role in salicylate-induced injury, we subjected guinea pigs to treatment with a specific inhibitor zDEVD-FMK via the round window niche (RWN) followed by a systemic injection of salicylate at a dose of 200 mg · kg(-1) · d(-1) i.p. for 10 consecutive days. For those animals administered with salicylate, immunohistochemical studies revealed that caspase-3 was activated in the spiral ganglion neurons (SGNs) and method of terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL) to identify neuronal apoptosis showed that fragmented nuclei were distributed in Rosenthal's canal. Topical administration of the zDEVD-FMK at a concentration of 500 mM blocked caspase-3 activation and had an effect in reducing the number of TUNEL-positive auditory neurons. In contrast, the inhibitor at a concentration of 125 or 250 mM caused no variation in the expression of activated caspase-3, or in the ratio of TUNEL-positive neurons. These results indicate that caspase-3 is a crucial mediator of apoptosis induced by salicylate in the primary auditory neuron in vivo, and suggest that the specific inhibitor at a relatively high concentration may be therapeutically beneficial in salicylate-induced apoptosis.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Cóclea
/
Apoptose
/
Ácido Salicílico
/
Caspase 3
/
Gânglios Espinais
Limite:
Animals
Idioma:
En
Revista:
Neurochem Res
Ano de publicação:
2011
Tipo de documento:
Article