Long-term effects of diabetes mellitus on voiding function in a new model of type 2 diabetes mellitus, the Spontaneously Diabetic Torii (SDT) rat.

The spontaneously diabetic Torii (SDT) rat has recently been established as a model of type 2 diabetes mellitus (DM). The usefulness of this rat model for the study of diabetic voiding dysfunction was investigated. Male SDT rats and male Sprague-Dawley (SD) rats were used. Voiding function was evaluated by a metabolic cage study and cystometry. Total voided volume for 24 h, mean voided volume, and urinary frequency for 24 h were significantly greater in SDT rats at the age of 36 weeks. From cystometry mean inter-micturition interval (IMI) was significantly longer in SDT rats at the age of 22 and 36 weeks. In SDT rats mean IMI was significantly longer at the age of 36 weeks than at the age of 22 weeks. Mean voiding pressure was significantly higher in SDT rats at the age of 22 and 36 weeks. In the present study, SDT rats showed typical diabetic voiding dysfunction similar to other diabetic rat models. It was suggested that activity of the bladder afferent pathways is decreased and the urethral relaxation mechanism is impaired in SDT rats. In addition, SDT rats are suitable to study chronic diabetic voiding dysfunction because they survive without insulin treatment for as long as 60 weeks.