Ischemic tolerance in the cochlea.

Ischemic tolerance in the cochlea was investigated in a gerbil model of cochlear ischemia. Transient cochlear ischemia was produced by extracranial occlusion of the bilateral vertebral arteries. The gerbils were divided into two groups; single ischemia group and double ischemia group. In the single ischemia group, animals were subjected to lethal cochlear ischemia for 15min. In the double ischemia group, animals were subjected to sublethal cochlear ischemia for 2min at 2 days before lethal ischemia for 15min. Consequently, sublethal ischemia prevented lethal ischemia-induced hair cell degeneration and ameliorated hearing impairment, suggesting ischemic tolerance in the cochlea.