[The effects of oxidative damage induced by organic oxidant t-BHP on cochlear hair cells].
OBJECTIVE
To establish the oxidative damage model of cochlea hair cells using organic oxidant t-BHP in vitro.


METHODS
HEI-OC1 cells were exposed to t-BHP at 8 doses (30~4000 µmol/L) for 12 h. Trypan blue test was used to detected the cellular viability and MTT assay was utilized to measured the cellular proliferation. The intracellular ROS levels were determined by 2,7-dichlorodihydrofluorescein diacetate (DCFH-DA).


RESULTS
The survival rates of HEI-OC1 cells started decrease significantly at the dose of 100 µmol/L t-BHP, the peak of decreased survival rates appeared at the doses of 200~800 µmol/L. The results of MTT assay demonstrated that 30 µmol/L t-BHP could promote cellular proliferation ability, when t-BHP concentrations were higher than 200 µmol/L, the cellular proliferation ability was inhibited. The results of DCFH-DA assay showed that there was no fluorescence in control group, the strong fluorescence was observed in positive control group, the weak fluorescence was observed in 30~50 µmol/L t-BHP groups, the bright fluorescence was observed in 100 µmol/L t-BHP group, still the stronger fluorescence was observed in 200~1000 µmol/L groups, but the cellular number decreased with the doses because of the lower cellular viability.


CONCLUSIONS
The exposure to 100 µmol/L t-BHP for 12 h could simulate the oxidative damage induced by noise in cochlear hair cells.
Guangdong Prevention and Treatment Centre for Occupational Disease, Guangzhou 510620, China.
Li-mei
LM
Chen
Xiao
X
Guo
Xu-dong
XD
Li
Zhi
Z
Wang
Yi-min
YM
Liu
D002470:Cell Survival; D002478:Cells, Cultured; D006198:Hair Cells, Auditory / Q000187:drug effects* / Q000473:pathology*; D006801:Humans; D009622:Noise / Q000009:adverse effects; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D017382:Reactive Oxygen Species / Q000032:analysis; D020122:tert-Butylhydroperoxide / Q000633:toxicity*
D017382:Reactive Oxygen Species; D020122:tert-Butylhydroperoxide