Metabolic Markers Associated with Progression of Type 2 Diabetes Induced by High-Fat Diet and Single Low Dose Streptozotocin in Rats

SIMPLE SUMMARY: Our experimental model of T2DM in rats is based on the development of insulin resistance induced by a four-week high-fat diet leading to obesity and pancreatic β-cell dysfunction caused by streptozotocin (STZ). Changes in anthropometric parameters, glucose, insulin, lipids, uric acid, advanced oxidation protein products (AOPP), as well as the histological changes in the liver and pancreas, were recorded. To assess insulin resistance, we used the Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) and beta cell function (HOMA-β) and visceral obesity—adiposity index (AI). The data demonstrate that the increasing values of glucose, HOMA-IR, AI, total cholesterol, triacylglycerols, low- and very-low-density lipoproteins are important markers of the pre-diabetic state induced by a long-term intake of a high-fat diet. Early metabolic markers of the disease were persistent hyperglycemia and hypercholesterolemia, as well as increased uric acid, HOMA-IR and decreased HOMA-β. The progression of T2DM in rats was characterized by hyperglycemia, hypercholesterolemia, hypertriacylglyceridaemia, an increase in lipoproteins, AI, uric acid, AOPP, HOMA-IR and decreased HOMA-β. A precise combination of several easily accessible metabolic markers is necessary to provide accurate information about T2DM in rats. ABSTRACT: Science is still searching for readily available, cost-effective biomarkers to assess metabolic disorders occurring before the onset and during the development of type-2 diabetes (T2DM). The aim of the present study was to induce T2DM in rats through a high-fat diet, followed by a single administration of low dose streptozotocin (STZ), and make an assessment of the development of the disease. The rats were divided into two groups—experimental and control—and were monitored for a period of 10 days. Changes in anthropometric parameters, glucose, insulin, lipids, uric acid, advanced oxidation protein products (AOPP), as well as the histological changes in the liver and pancreas, were recorded. To assess insulin resistance, we used the Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) and beta cell function (HOMA-β) and visceral obesity—adiposity index (AI). The data demonstrate that the increasing values of glucose, HOMA-IR, AI, total cholesterol, triacylglycerols, low- and very-low-density lipoproteins are important markers of the pre-diabetic state. The stable hyperglycemia and increased levels of TC, TG, VLDL, LDL, uric acid and AOPP in experimental rats strongly suggest the development of T2DM. HOMA-IR, HOMA-β, AI, and uric acid are reliable criteria for T2DM in rats.