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International Journal of Experimental Diabetes Research
Volume 1, Issue 2, Pages 89-100
http://dx.doi.org/10.1155/EDR.2000.89

A New Spontaneously Diabetic Non-obese Torii Rat Strain With Severe Ocular Complications

1Research Laboratories, Torii Pharmaceutical Co., Ltd., 1-2-1, Ohnodai, Midori-ku, Chiba 267-0056, Japan
2Division of Laboratory Animal Science, Animal Research Center, Tokyo Medical University, Shinjuku-ku, Tokyo 160-0022, Japan
3Omiya Medical Center, Jichi Medical School, Amanuma-cho, Omiya 330-0834, Japan
4Japan Tobacco Inc., Toxicology Research Laboratories, Central Pharmaceutical Institute, 23 Nakogi, Hatano, Kanagawa 257-0024, Japan
5Japan Tobacco Inc., Central Pharmaceutical Research Institute, 1-1 Murasaki-cho, Takatuki, Osaka 569-1125, Japan

Received 24 October 1999; Accepted 30 December 1999

Copyright © 2000 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

A new spontaneously diabetic strain of the Sprague-Dawley rat was established in 1997 and named the SDT (Spontaneously Diabetic Torii) rat. In this research, we investigated the characteristics of the disease condition in 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. Glucose intolerance was observed in male rats from 16 weeks of age. The clinical characteristics of the male SDT rats were (1) hyperglycemia and hypoinsulinemia (from 25 weeks of age); (2) long-term survival without insulin treatment; (3) hypertriglyceridemia (by 35 weeks of age); however, no obesity was noted in any of the male rats. The histopathological characteristics of the male rats with diabetes mellitus (DM) were (1) fibrosis of the pancreatic islets (by 25 weeks of age); (2) cataract (by 40 weeks of age); (3) tractional retinal detachment with fibrous proliferation (by 70 weeks of age) and (4) massive hemorrhaging in the anterior chamber (by 77 weeks of age). These clinical and histopathological characteristics of the disease in SDT rats resemble those of human Type 2 diabetes with insulin hyposecretion. In conclusion, SDT rat is considered to be a potentially useful model for studies of diabetic retinopathy encountered in humans.