The method of detecting the apoptotic hair cells at their early stage in the cochlea

Objective:To introduce a method of detecting the apoptotic hair cells at their early state in the cochlea. Methods:Guinea pigs were exposed to 75 pairs of impulse noise （1 second interval between each pair） at 155 dB pSPL. 5 min after the noise exposure, the organs of corti were processed for detection of hair cell death modes. The apoptotic hair cells were distinguished by double-stained using FITC-labeled phalloidin for filamentous actin （F-actin）,propidium iodide （PI） for hair cell nuclei and confirmed by staining for TUNEL assay. The specimens were examined under a fluorescence microscope for assessment of the hair cell damage. Results:Some slightly condensed nuclei can maintain the integrity of F-actin staining in the tissue double-stained with FITC-labeled phalloidin and PI. In TUNEL labeled cochlea, there is strong green fluorescence in the condensed nuclei. Conclusion:The method of double-stained with FITC-labeled phalloidin and PI can be used to distinguish the apoptotic hair cells at their early state.