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Journal of Diabetes Research
Volume 2013 (2013), Article ID 986462, 9 pages
http://dx.doi.org/10.1155/2013/986462
Research Article

Phenotypic Characterization of LEA Rat: A New Rat Model of Nonobese Type 2 Diabetes

1Department of Laboratory Animal Medicine, National Center for Global Health and Medicine, Tokyo 162-8655, Japan
2Department of Infectious Diseases, National Center for Global Health and Medicine, Tokyo 162-8655, Japan
3Institute for Animal Experimentation, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan
4Department of Comparative and Experimental Medicine, Nagoya City University Graduate School of Medical Sciences, Nagoya 467-8601, Japan
5Center for Experimental Animal Science, Nagoya City University Graduate School of Medical Sciences, Nagoya 467-8601, Japan
6Institute of Laboratory Animals, Tokyo Women's Medical University, Tokyo 162-8666, Japan
7Division of Diabetes and Metabolism, Department of Internal Medicine, Iwate Medical University School of Medicine, Morioka 020-8505, Japan
8Pathology Section, Department of Clinical Research, National Hospital Organization Hakodate National Hospital, Hakodate 041-8512, Japan

Received 23 November 2012; Accepted 26 December 2012

Academic Editor: Norihide Yokoi

Copyright © 2013 Tadashi Okamura et al. 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

Animal models have provided important information for the genetics and pathophysiology of diabetes. Here we have established a novel, nonobese rat strain with spontaneous diabetes, Long-Evans Agouti (LEA) rat derived from Long-Evans (LE) strain. The incidence of diabetes in the males was 10% at 6 months of age and 86% at 14 months, while none of the females developed diabetes. The blood glucose level in LEA male rats was between 200 and 300 mg/dl at 120 min according to OGTT. The glucose intolerance in correspondence with the impairment of insulin secretion was observed in male rats, which was the main cause of diabetes in LEA rats. Histological examination revealed that the reduction of -cell mass was caused by progressive fibrosis in pancreatic islets in age-dependent manner. The intracytoplasmic hyaline droplet accumulation and the disappearance of tubular epithelial cell layer associated with thickening of basement membrane were evident in renal proximal tubules. The body mass index and glycaemic response to exogenous insulin were comparable to those of control rats. The unique characteristics of LEA rat are a great advantage not only to analyze the progression of diabetes, but also to disclose the genes involved in type 2 diabetes mellitus.