Type 2 Diabetes Mellitus, Hyperlipidemia, and Extremity Lesions in California Mice (Peromyscus californicus) Fed Commercial Mouse Diets

Background and Purpose: We characterized abnormalities of carbohydrate and lipid metabolism and determined whether those metabolic abnormalities are associated with extremity lesions in California mice (Peromyscus californicus). Methods: Blood samples were evaluated for glucose, cholesterol, triglyceride, and insulin concentrations. Necropsy and histologic evaluation were done on selected mice, including staining pancreatic sections for insulin. Physical examinations also were performed. Results: California mice were found to have Type 2 diabetes mellitus (T2DM). Sections of pancreas from diabetic and prediabetic mice had pathologic changes consistent with T2DM. After six months of feeding a low-fat diet, mice were normoglycemic, normotriglyceridemic, and normocholesterolemic. Some mice remained hyperinsulinemic. Traumatic lesions were not associated with T2DM. Conclusions: California mice develop diet-related T2DM when fed a diet containing 25.8% kcal from fat. California mice may be a useful animal model of human T2DM, and traumatic lesions result from housing California mice in multiple male groups.