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)-Lepr(db)/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 mu m) was greater than that in the control group (2.388 +/- 0.411 mu m). 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 mu m, 14 weeks; 294.378 +/- 151.008 mu m, and 28 weeks; 312.925 +/- 147.943 mu m). 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