The cochlea of the spontaneously diabetic mouse. II. Electron microscopic observations of non-obese diabetic mice.

We used transmission electron microscopy to examine the cochlea of non-obese diabetic mice as animal models for human type I or non-insulin-dependent diabetes mellitus. Pathological changes were observed in the organ of Corti of the basal turn and in the stria vascularis of each turn. Major findings in the stria vascularis were protrusion or condensation of marginal cells, swelling of intermediate cells, and widening of the intercellular spaces. Principal findings in the organ of Corti involved degenerative changes of the outer and inner hair cells and replacement of hair cells by supporting cells. No prominent pathological changes were observed in the capillaries. The possible mechanism of diabetic involvement in cochlear pathology is discussed.