Background: Experimental models are essential for clarifying the pathogenesis of diabetes mellitus (DM). We aimed to provide an exhaustive description of clinical, biochemical, and hematologic features of rats with streptozotocin (STZ)-induced DM.
Methods: Wistar rats were assigned to control (n=14) or DM (n=17) groups. DM was induced using STZ (60 mg/kg, i.p.). If STZ failed to induce DM, rats were reinjected with a similar STZ dose. Bodyweight, 24-h food and water intake were measured weekly during 28 weeks. At the end of the study lipid profile, kidney function, and complete blood count were assessed.
Results: STZ induced DM in 58.82% of rats. The second STZ administration induced DM in 71.43% of the remaining rats. Diabetics presented progressive, but less significant bodyweight increase than controls, and higher food and water consumption. At the end of the study, diabetics presented higher white blood cells count, glucose, triglycerides, total and low-density lipoprotein cholesterol, and lower creatinine clearance than controls (all p≤0.02). No significant difference was observed between diabetics injected once and those that were reinjected, in any of the studied parameters.
Conclusions: This study provides one of the longest follow-ups of rats with STZ-induced type 1 DM, demonstrating that the STZ-diabetic rat replicates the most relevant clinical, biochemical, and hematologic features of human diabetes. The present data also indicate, for the first time, that rats with initial unsuccessful STZ administration can be safely reinjected, with outcomes similar to those seen in rats receiving a single injection.