Development and characterization of a high fat diet-streptozotocin induced type 2 diabetes model in nude athymic rats

People with diabetes mellitus (DM) are at an increased risk for myocardial infarction (MI) than age matched people without DM. However, assays for pre-clinical therapy are performed in animal models of ischemia that lack the co-morbid conditions present in patients with MI, such as DM. This contributes to the failure to translate pre-clinical trials results to the clinic. Thus, to increase the clinical relevance of xenograft studies in pre-clinical models, it is important to have a DM model in animals that are immunodeficient. Here, we developed a type 2 diabetes mellitus (T2D) model in nude athymic rats using high-fat diet and streptozotocin (HFD-STZ). Nude athymic rats were randomized into a control group (normal chow) or a HFD (45% fat, 20% protein and 35% carbohydrate)-STZ group. STZ (35 mg/kg i.v.) or vehicle was administered 8 weeks after HFD feeding started. Assessments were done longitudinally and at week 9 (endpoint). The HFD-STZ group showed mild hyperglycemia pre STZ administration (7.7 {+/-} 0.3 mM vs 5.8 {+/-} 0.2 mM in control) by week 8. In addition, plasma insulin levels were increased and the HOMA index was 2.5-times higher in the HFD-STZ. The HFD-STZ group showed increased fasting (147%) triglycerides. After STZ-administration, blood glucose levels increased substantially (23.6 {+/-} 1.4 mM vs 5.5 {+/-} 0.3 mM in control). The HFD-STZ treated animals also showed increased left ventricular wall thickness, cardiac hypertrophy and fibrosis, reduced cardiac function compared to normal chow control. In line with the HFD-STZ model in immunocompetent rats, the HFD-STZ treatment of athymic rats recapitulates key features of T2D, including aspects of established clinical diabetic cardiomyopathy and should be suitable for xenograft studies in the context of T2D.