Research Article

Ouabain-Induced Apoptosis in Cochlear Hair Cells and Spiral Ganglion Neurons In Vitro

Figure 4

Apoptotic labeling in HCs and SGNs after ouabain treatment in cochlear organotypic cultures. (a) There was no evidence of positive Annexin V labeling in HCs 24 h after 50 μM ouabain treatment, although the stereocilia were disarrayed on the HCs. (b) In the same culture conditions as (a), apoptotic signals were detected in some SGNs (arrow). (c) Annexin V positive labeling was seen in HCs and the supporting cells in the region of the lateral sulcus 24 h after 500 μM ouabain treatment. (d) In the same culture conditions as (c), with 500 μM ouabain, most SGNs presented with positive Annexin V expression (arrows) showing apoptotic features (fluorescence microscope at a magnification of ×600). (e) At 24 h after 50 μM ouabain treatment, a quarter of the SGNs exhibited FITC-Annexin V positive labeling. (f) At 24 h after 500 μM ouabain treatment, the FITC-Annexin V positive labeling of SGNs was increased to 65%.