Effects of Diabetes Mellitus on the Biomechanical Properties of the Female Rat Urethra in the Passive State

Patients with diabetes mellitus (DM) suffer impaired lower urinary tract dysfunctions. The purpose of the current study was to evaluate the effects of DM on the passive biomechanical properties of the female rat urethra. DM was induced by injection of streptozotocin. Urethras were excised and mounted in an ex-vivo testing system. EDTA was added to the bath to inactivate smooth muscle. Continuous outer diameter measurements were made at proximal, middle, and distal portions of the urethra with a laser micrometer during stepwise increases of static, intraurethral pressure (0 to 20 mmHg). Compliance and beta stiffness were calculated from measured data. Healthy urethras served as controls. Statistical comparisons were made via ANOVA. The control tissue was most compliant proximally and decreased significantly along the length. This compliance gradient vanished with DM. A significant decrease in compliance and increase in beta stiffness was noted for 10 wk DM compared to controls. These findings suggest that DM has a large effect on the biomechanical properties of the urethra.