Tumor Necrosis Factor-α-Induced Ototoxicity in Mouse Cochlear Organotypic Culture
Fig 2
Transmission electron microscopy of stereocilia bundles and organelles of organ of Corti.
A,B) Bundles of stereocilia in outer hair cells are arranged orderly and central filaments are straightly inserted into the cuticular plate in control cultures after 2 days. C–G) After treatment with 20 μg/mL tumor necrosis factor (TNF)-α, general phalloidin-labeled stereocilia bundles appear disorderly by a immunofluorescence image (C), and collapse (D, E) and endocytosis (F, G) of the bundles into the hair cell body were observed. H) Mitochondria in control cultures contained normal outer, inner, and cristal membranes. The endoplasmic reticulum membrane was intact and smooth (arrow). I) Treatment of cultures for 2 d with 20 μg/mL tumor necrosis factor (TNF)-α resulted in enlargement, vacuolation and fission of mitochondria in outer hair cells. J) TNF-α treatment also caused swelling of the endoplasmic reticulum, and rough endoplasmic reticulum was degranulated (arrow). K) The tight junction (arrow) in the control cultures showed a normal electron density. L) Tight junction integrity was disrupted and with a hazy electron density (arrow) after 2 d with 20 μg/mL TNF-α. Scale bars: 0.20 μm.