Authors: A Rewerska M Pawelczyk E Rajkowska P Politanski M SliwinskaKowalska
Publish Date: 2012/11/18
Volume: 270, Issue: 4, Pages: 1513-1520
Abstract
Noise exposure causes an excessive reactive oxygen species ROS generation as an unwanted byproduct of high metabolic activity Oxidative stress and antioxidative protective mechanisms have been therefore proposed as the most interesting issues in the development of noiseinduced hearing loss The aim of this study was to examine changes in superoxide dismutase SOD catalase CAT and the auditory brainstem response ABR in the cochlea of C57BL/6 mice 1 7 and 14 days after exposure to 4 kHz octave band noise at the intensity of 110 dB SPL for 8 h The evaluation of three dmethionine dmet doses 100 200 and 400 mg/kg has been performed in order to choose an optimal concentration displaying most effectively its antioxidant and thereby otoprotective functions Administering dmet at the dose of 400 mg/kg resulted in a significant decrease in threshold shift TS independently of the evaluation time after exposure to noise SOD activity was strongly supported by the same concentration 400 mg/kg of dmet This effect was seen not shortly but 7 and 14 days after exposure to noise CAT activity was induced only by noise and it reached the peak levels 7 days after exposure dMet at the doses of 200 and 400 mg/kg significantly decreased noiseinduced changes in CAT activity The findings of this study indicate that the protective effect depends on the concentration of dmet and can be fully expressed only when the drug is administered in the dose 400 mg/kg
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