Selective degeneration of synapses in the dorsal cochlear nucleus of chinchilla following acoustic trauma and effects of antioxidant treatment.

The purpose of this study was to reveal synaptic plasticity within the dorsal cochlear nucleus (DCN) as a result of noise trauma and to determine whether effective antioxidant protection to the cochlea can also impact plasticity changes in the DCN. Expression of synapse activity markers (synaptophysin and precerebellin) and ultrastructure of synapses were examined in the DCN of chinchilla 10 days after a 105 dB SPL octave-band noise (centered at 4 kHz, 6 h) exposure. One group of chinchilla was treated with a combination of antioxidants (4-hydroxy phenyl N-tert-butylnitrone, N-acetyl-l-cysteine and acetyl-l-carnitine) beginning 4 h after noise exposure. Down-regulated synaptophysin and precerebellin expression, as well as selective degeneration of nerve terminals surrounding cartwheel cells and their primary dendrites were found in the fusiform soma layer in the middle region of the DCN of the noise exposure group. Antioxidant treatment significantly reduced synaptic plasticity changes surrounding cartwheel cells. Results of this study provide further evidence of acoustic trauma-induced neural plasticity in the DCN and suggest that loss of input to cartwheel cells may be an important factor contributing to the emergence of hyperactivity in the DCN after noise exposure. Results further suggest that early antioxidant treatment for acoustic trauma not only rescues cochlear hair cells, but also has impact on central auditory structures.

Du X ，Chen K ，Choi CH ，Li W ，Cheng W ，Stewart C ，Hu N ，Floyd RA ，Kopke RD ... -  《-》

Candidate's thesis: enhancing intrinsic cochlear stress defenses to reduce noise-induced hearing loss.

Kopke RD ，Coleman JK ，Liu J ，Campbell KC ，Riffenburgh RH ... -  《LARYNGOSCOPE》

Intense sound-induced plasticity in the dorsal cochlear nucleus of rats: evidence for cholinergic receptor upregulation.

Kaltenbach JA ，Zhang J 《HEARING RESEARCH》

Effectiveness of 4-hydroxy phenyl N-tert-butylnitrone (4-OHPBN) alone and in combination with other antioxidant drugs in the treatment of acute acoustic trauma in chinchilla.

Choi CH ，Chen K ，Vasquez-Weldon A ，Jackson RL ，Floyd RA ，Kopke RD ... -  《FREE RADICAL BIOLOGY AND MEDICINE》

Pharmacological rescue of noise induced hearing loss using N-acetylcysteine and acetyl-L-carnitine.

Coleman JK ，Kopke RD ，Liu J ，Ge X ，Harper EA ，Jones GE ，Cater TL ，Jackson RL ... -  《HEARING RESEARCH》