The Rat Model of Type 2 Diabetic Mellitus and Its Glycometabolism Characters

Abstract

Abstract:To develop a rat model of type 2 diabetic mellitus that simulated the common manifestation of the metabolic abnormalities and resembled the natural history of a certain type 2 diabetes in human population, male Sprague-Dawley rats (4 months old) were injected with low-dose (15 mg/kg) STZ after high fat diet (30% of calories as fat) for two months (L-STZ/2HF). The functional and histochemical changes in the pancreatic islets were examined. Insulin-glucose tolerance test, islet immunohistochemistry and other corresponding tests were performed and the data in L-STZ/2HF group were compared with that of other groups, such as the model of type 1 diabetes (given 50 mg/kg STZ) and the model of obesity (high fat diet). The body weight of rats in the group of rats given 15 mg/kg STZ after high fat diet for two months increased significantly more than that of rats in the group of rats given 50 mg/kg STZ (the model of type 1 diabetes) (595 ± 33 g vs. 352 ± 32 g, p<0.05). Fast blood glucose levels for L-STZ/2HF group were 16.92 ± 1.68 mmol/l, versus 5.17 ± 0.55 mmol/l in normal control and 5.59 ± 0.61 mmol/l in rats given high fat diet only. Corresponding values for fast serum insulin were 0.66 ± 0.15 ng/ml, 0.52 ± 0.13 ng/ml, 0.29 ± 0.11 ng/ml, respectively. Rats of type 2 diabetes (L-STZ/2HF) had elevated levels of triglyceride (TG, 3.82 ± 0.88 mmol/l), and cholesterol(Ch, 2.38 ± 0.55 mmol/l) compared with control (0.95 ± 0.15 mmol/l and 1.31 ± 0.3 mmol/l, respectively) (p<0.05). The islet morphology as examined by immunocytochemistry using insulin antibodies in the L-STZ/2HF group was affected and quantitative analysis showed the islet insulin content was higher than that of rats with type 1 diabetes (P<0.05). We concluded that the new rat model of type 2 diabetes established with conjunctive treatment of low dose of STZ and high fat diet was characterized by hyperglycemia and light impaired insulin secretion function accompanied by insulin resistance, which resembles the clinical manifestation of type 2 diabetes. Such a model, easily attainable and inexpensive, would help further elucidation of the underlying mechanisms of diabetes and its complications.

Method for liver tissue metabolic profiling study and its application in type 2 diabetic rats based on ultra performance liquid chromatography–mass spectrometry

“…The animals were successively intragastric administration with fat milk for 20 days and abdominal cavity injection with streptozotocin (STZ) 45 mg/kg. After fasting 72 h, those with the blood glucose over 11 mmol/L were taken as successful modeling and involved in the T2D group [27,28]. Sample preparation was carried out in 'Section 2.3' and a 5 L aliquot of the reconstructed solution was injected into the UPLC-Q-TOF/MS system.…”

Diastolic function of the right ventricle is impaired in experimental type 2 diabetic rat models

“…Type 2 diabetes is characterized by reduced insulin sensitivity (insulin resistance) and higher blood glucose. In the present experiment, insulin resistance was induced by a high-fat diet initially (11). Thereafter, a low-dose STZ injection slightly reduced the number of β cells, which eventually resulted in hyperglycemia (12).…”

Attenuation of hyperglycemia and hyperlipidemia in high calorie fed/streptozotocin-treated rats by hydromethanolic extract of <i>Padina tetrastromatica</i>

“…In the present study, the pathophysiological conditions of human type II DM was demonstrated in experimental animals by feeding them with a HCD for two months followed by an intraperitoneal injection of mild dose of STZ following the procedures described elsewhere (Wang et al, 2007;Zhang et al, 2003). From the preliminary physiological and biochemical observations, it was obvious that we succeeded in establishing the typical characteristics of human type II DM in experimental rats.…”

“…All rats could eat and drink ad libitum. After two months of HCD feeding, streptozotocin (STZ) at a dose of 15 mg/ kg body weight (Zhang et al, 2003) in 0.1 M citrate buffer (pH 4.6) was injected intraperitoneally. Seventytwo hours after STZ injection, the fasting blood glucose levels were measured and animals having blood glucose values greater than 300 mg/dL were selected for further experimentation.…”