Mechanism of Hair Cell Apoptosis in Age-related Hearing Loss Mouse Cochlea / 听力学及言语疾病杂志

ABSTRACT

Objective In this study,we investigated the hair cell apoptosis and the molecular mechanisms in age-related hearing IOSS mouse cochlea.Methods All animals were assessed by ABR and DPOAE analysis in both ears.TUNEL(Terminal dexynucleotidyl transferase(TdT)mediated dUTP Nick End Labeling)and PI were used to identify DNA fiagments and caspase-3 activities in hair cells.Results The results showed that the nmf308 mice had progressive hair cell loss along with age.The cochlear OHCs were reduced 5%～10% at 1 month and 100% at 3 month in the basal region.Substantial amounts of TUNEL-postive OHCs nuclei were observed at age of 1 month,and activated caspase-3 labeling OHCs were most obviously observed at age of 2 months.Conclusion These results suggest that DNA single strand break is attributed primarily to apoptosis of cochlear lesion,and activation of caspase-3 at leter stage leads to the hair cell apoptiovs of nuclear condensation in age-related hearing loss mouse cochlea.