Circulatory disturbance of the cochlear spiral modiolar artery in a type 2 diabetic mouse model.

ABSTRACT

Objective: This study aimed to identify significant differences in cochlea microvessel size between a diabetic mouse model (db/db) and normal mice using three-dimensional (3D) quantitative analysis. Methods: Six control heterozygote db/+ as well as 18 male B6/BKS(D)-Leprdb/J (db/db) mice aged 14 (n = 9) and 28 (n = 9) weeks were examined. After clearing the cochlea, we reconstructed the 3D volumes of the spiral modiolar artery (SMA) in the cochlea using light-sheet microscopy and analyzed vessel wall thickness, cross-sectional area, short and long diameter, and vessel height. Results: The average SMA-wall thickness in the db/db-mouse group (3.418 ± 0.328 µm) was greater than that in the control group (2.388 ± 0.411 µm). The average cross-sectional outer area, short diameter, and long diameter of the SMA in db/db mice were significantly larger than those in control mice (all p < 0.001). The cross-sectional areas increased with age (control 221.782 ± 121.230 µm, 14 weeks; 294.378 ± 151.008 µm, and 28 weeks; 312.925 ± 147.943 µm). Conclusion: The db/db mice had thicker and larger proximal-SMA vessel walls and diameters than control mice, respectively, thus potentially inducing increased blood viscosity or vascular insufficiency and aggravating hearing loss in type 2 diabetes mellitus. Level of Evidence IIb.