[Study of the effect of JNK signal transduction pathway in intense noise-induced apoptosis in cochlea of guinea pig].
OBJECTIVE
To investigate the mechanism of intense noise-induced cochlea cells death in guinea pig, and the effect of JNK signal transduction pathway in the procedure of cochlea cells apoptosis by intense noise-induced.


METHODS
Thirty-two guinea pigs were randomly divided into 4 groups. The guinea pigs in the experiment groups were exposed to 4 kHz narrow band noise at 120 dB SPL for 4 h. After the noise expose for 1, 4, 14 days of the experiment guinea pigs, ABR of the guinea pigs on experiment and control groups were tested before put them to death. Four guinea pig's cochleas of every group were taken to paraffin section, and the rest was extracted the total cochlear's protein. Apoptosis was tested by terminal deoxynucleotidyl Transferase (TdT)-mediated deoxyuridine triphosphate (d-UTP) nick and labeling method (TUNEL). The phosphorylation of JNK and c-Jun were tested by immunohistochemistry and western blot methods.


RESULTS
Tunel-Positive cells in the Corti's, SGC and SV of experiment groups, and there have significant differences compared with the control group (P<0.01) and Tunel-Positive cells are most in 1 d experiment group. The positive cells of P-JNK and P-c-Jun could be detected in guinea pig's cochleas after noise exposed, but no positive cells were found in the control. Protein levels of P-JNK and P-c-Jun were risen up and activated quickly after noise exposed, and achieved peak in 1 d, 4 d and then fallen-offs, but still maintained higher levels within 14 d.


CONCLUSIONS
Intense noise causes cochlea cell lesion by inducing apoptosis to result in and JNK signal transduction pathway plays an important role in the procedure of apoptosis.
Xue
Qiuhong
Q
Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China. xueqh815@hotmail.com
Chen
Jia
J
Gong
Shusheng
S
Xie
Jing
J
He
Jian
J
Chen
Xiaolin
X
D000818:Animals; D017209:Apoptosis; D003051:Cochlea / Q000378:metabolism* / Q000473:pathology*; D006168:Guinea Pigs; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism*; D008297:Male; D009622:Noise / Q000009:adverse effects*; D015398:Signal Transduction
D048031:JNK Mitogen-Activated Protein Kinases