Hair cell death in a hearing-deficient canary

Cell death has been documented in bird auditory inner ear epithelia after i nduced damage. This cell death is quickly followed by an increase in suppor ting cell division and regeneration of the epithelium, thereby suggesting a possible relationship between these two processes. However, aspects of thi s relationship still need to be better understood. The Belgian Waterslager (BWS) canary is an ideal system in which to study cell death and subsequent cell division. In contrast to mixed breed (MB) canaries, cell division nor mally occurs in the auditory end organ of the BWS without any external mani pulation. In addition, some of the cells in the auditory epithelium may be dying through an apoptotic-like process. In the present study two methods w ere used to quantify dying cells in the BWS and MB canary auditory epitheli a: morphological criteria and TUNEL. Results confirm that some of the abnor mal hair cells in the BWS auditory epithelium are apoptotic-like. The prese nce of both cell death and cell division indicates that these processes act concurrently in the adult end organ. Future studies are needed to determin e if cell death is a stimulus for the observed cell division.