QUANTITATIVE MEASURES REFLECT DEGENERATION, BUT NOT REGENERATION, IN THE DEAFNESS MOUSE ORGAN OF CORTI

The deafness mouse (dn/dn) is a well known model of hereditary deafnes s uncomplicated by behavioral and motor disturbances. The organ of Cor ti in this mouse develops a normal complement of sensory and supportin g cell structures, yet animals homozygous for this gene never demonstr ate tiny hearing capacity. They are profoundly deaf from birth. Soon a fter development, the organ of Corti rapidly degenerates, most sensory cells having vanished by 50 days of age. Published observations have suggested that apical regions of the organ of Corti may regenerate som e supporting cell structures by 90 days of age. We have quantified cha nges in organ of Corti structure from 15 to 130 days of age using seve ral different measures. Measures of peak height and total cross-sectio nal area, as well as a subjective rating scale, all demonstrate consis tent degenerative changes during this time period. No evidence for reg eneration of supporting or sensory cell structures is noted, although a surprising degree of variability is present in all regions of the or gan of forti which may account for previous claims. (C) 1998 Elsevier Science B.V.