The nature and progression of injury in the organ of Corti during ischemia.

This study has defined the nature and sequence of ultrastructural changes in the organ of Corti following severe, total cochlear ischemia. Afferent nerve endings of IHC became swollen within 15 min and eventually ruptured. Outer hair cells were swollen within 30 min and showed alterations to mitochondria, endoplasmic reticulum and the nucleus whereas IHC remained unchanged for up to 60 min. Both efferent and afferent nerve endings of OHC were unaltered until after 60 min ischemia. Regardless of the type, cells in the base of the cochlea developed abnormalities more rapidly than those in the apical turns. These results imply a differential susceptibility to ischemic damage both among the different cell types and along the organ of Corti.