ABSTRACT
Aim: The Spontaneously Diabetic Torii (SDT) fatty rat is a novel obese type 2 diabetic model, showing hyperphagia, obesity, and diabetes mellitus from a young age. In this study, we investigated the effects of isolation stress on pathophysiology in SDT fatty rats. Methods: SDT fatty rats (4 weeks old) were housed 3 per cage for 2 weeks and separated as males or females so as each gender will be placed in a separate cage to avoid mating. After acclimatization in 6 weeks of age, the rats were exposed to isolation stress (IS) (one rat per cage, using 5 animals in each sex). In the control group, each sex of experimental rats were housed separately continuously 3 per cage (using 6 animals in each sex). Food intake, body weights, and blood chemical parameters, such as glucose, insulin, triglyceride and total cholesterol levels, of the rats from 6 to 15 weeks of age were measured at every 3 weeks. Satellite groups were prepared for pathological analyses. Necropsy of satellite group was performed at 12 weeks of age, and the pathological analyses, such as adrenal, thymus and spleen, were performed. Results: The blood glucose level in IS group in female SDT fatty rats was significantly increased at 12 weeks of age as compared with that in control group. Female SDT fatty rats showed accelerated diabetic progression, but the male rats did show the effects of IS on the glucose/lipid metabolism. In male SDT fatty rats, an increase of adrenal weight and a decrease of thymus weight were observed in IS group and the female rats in IS group showed a tendency of an increase of adrenal weight and a decrease of thymus weight. In histopathological analyses, adrenal hypertrophy and thymus atrophy were observed in IS group in both male and female rats. Conclusion: Isolation stress affected the progression of diabetes in female SDT fatty rats. Housing conditions is a factor to care for in evaluation of pathophysiology in diabetic models.
ABSTRACT
Aim: The Spontaneously Diabetic Torii (SDT) fatty rat is a metabolic syndrome model, showing obesity, hyperglycemia, dyslipidemia, and hypertension. Moreover, female SDT fatty rats exhibit hepatic steatosis. In this study, metabolic abnormalities, particularly in the liver, were assessed in male SDT fatty rats fed a diet containing 40% fat and 2% cholesterol (HFC-diet). Location and Duration of Study: Niigata University, CLEA Japan and JT Central Pharmaceutical Research Institute, between January and December 2014. Methodology: Male SDT fatty rats in control and HFC groups were fed a standard or HFC-diet (40% fat and 2% cholesterol, based on percentage of total calories) from 5 to 17 weeks of age, respectively. Body weight and blood chemistry parameters were periodically measured and a pathological analysis of the liver was performed at 17 weeks of age. Results: In biological analyses, the HFC group showed increases in body weight, blood insulin, and total cholesterol during the experimental period and an increase in aspartate aminotransferase (AST) at 13 weeks of age. Blood glucose levels in HFC group decreased after 13 weeks of age. In pathological examinations, an increase in liver weight and hepatic steatosis, fatty change and hypertrophy in hepatocyte, were observed in the HFC group. Hepatic steatosis was not observed in the standard-diet group. Conclusion: Male SDT fatty rats fed an HFC-diet may serve as a new nonalcoholic fatty liver disease (NAFLD) model.
ABSTRACT
Aim: This study was conducted to investigate the preventive or therapeutic effect of α- glucosidase inhibitor voglibose in a new model rat, Spontaneously Diabetic Torii-Leprfa (SDT fatty) rat, which is a novel type 2 diabetic rat showing obesity, hyperglycemia and hyperlipidemia from a young age. Place and Duration of Study: Niigata University and JT Central Pharmaceutical Research Institute, between January and August 2011. Methodology: The present study was designed to the preventive and therapeutic effect of voglibose by administering (0.3, 1 mg/kg) voglibose as a dietary admixture to SDT fatty rats from 5 to 11 and 14 to 20 weeks of age, respectively. Results: In the examination of preventive effect, the obtained biochemical results show that voglibose decrease glucose level significantly in dose-dependent manner within 5-11 weeks of age. In voglibose-treated rats at 11 weeks of age, the histopathological pancreatic changes, such as vacuolation and irregular boundaries in islets, were improved. On the other hand, in the examination of therapeutic effect, voglibose improved the hyperglycemia only at a dose of 1 mg/kg within 16-20 weeks of age. Conclusion: Voglibose showed both preventive and therapeutic effects for diabetes in female SDT fatty rats. The SDT fatty rat is a useful model for development of anti-diabetic agents.