Establishment and Clinical Features in Spontaneously Diabetic Torii Rat

The Spontaneously Diabetic Torii (SDT) rat is a spontaneous animal model of non-obese Type 2 diabetes (T2D) resembling those of humans, established in 1997. I investigated the clinical features of the SDT rats. The time of onset of glucosuria was different between male and female SDT rats; glucosuria appeared at approximately 20 weeks of age in male rats and at approximately 45 weeks of age in female rats. A cumulative incidence of diabetes of 100% was noted by 40 weeks of age in male rats, while it was only 33.3% even by 65 weeks of age in female rats. The survival rate up to 65 weeks of age was 92.9% in male rats and 97.4% in female rats. The male SDT rats were (1) hyperglycemia and hypoinsulinemia (from 25 weeks of age); (2) a significant increase in urea nitrogen levels, urinary protein excretion and HbA1c levels (from 35 weeks of age); (3) long-term survival without insulin treatment after onset of diabetes; additionally, no obesity was noted in any of the male and female rats. These results indicated that the SDT rat strain described here would serve as useful animal model for studies of non-obese T2D.