Pathophysiological Analysis of Female Spontaneously Diabetic Torii Fatty Rats

Abstract

Obesity, hyperglycemia, hyperlipidemia, and diabetes-associated complications appear at younger ages (6-8 weeks) in the male Spontaneously Diabetic Torii-Lepr fa (SDTfa/fa) rat than in the male original SDT (SDT-+/+) rat. However, the incidence and progression of diabetes mellitus and diabetic complications in the female SDT-fa/fa rat have not been reported in detail. In the present study, the pathophysiological features of the female SDT-fa/ fa rat were examined, and compared with those of the female SDT-+/+ rat. Female SDT-fa/ fa rats showed hyperphagia, obesity, hyperglycemia, and hyperlipidemia from 5 or 6 weeks of age, and hyperinsulinemia was observed from 5 to 12 weeks. Pathological changes pancreatic islets were observed from 8 weeks. Renal function parameters, such as urine volume and urinary protein, increased from 16 weeks, and pathological findings in the renal tubule, and cataracts were also observed from 16 weeks. Increases of visceral and subcutaneous fats were obvious during the observation period. In pair-feeding with SDT-+/+ rats, SDT-fa/fa rats showed improved hyperglycemia and hypertriglycemia, but hypercholesterolemia was not entirely improved during the study period. Female SDT-fa/fa rats showed diabetes mellitus and diabetes-associated complications at young ages, and fat accumulation was remarkable. Suppression of hyperphagia in SDT-fa/fa rats was effective at improving hyperglycemia and hypertriglycemia. In conclusion, the female SDT-fa/fa rat has the potential to become an important animal model of type 2 diabetes mellitus with obesity, especially for women, for which few models currently exist.

Evaluation of Blood Pressure in Spontaneously Diabetic Torii-Leprfa Rats

“…1 and 2. SDT-fa/fa rats showed obesity, hyperglycemia and hyperlipidemia during the experimental period in agreement with previous reports [4,9]. Obesity and hyperinsulinemia in SDT-fa/fa rats were observed only at 8 weeks of age.…”

“…Body weights and serum insulin levels of the SDT-+/+ rats decreased after 16 weeks of age (Table 1). Also, the increase of renal-related parameters such as BUN, urine volume, and urinary protein, was observed in SDT-fa/fa rats, similar to results reported in previous studies (Table 1) [4,10]. In addition to these changes, increases of serum leptin and urine angiotensinogen levels were shown by the SDT-fa/fa rats (Fig.…”

“…Body weight, serum parameters, except for the leptin level, and renal-related parameters except for the urine angiotensinogen level were determined in previous studies [4,8]. The results of the present study are shown in Table 1.…”

“…SDT-fa/fa rats exhibit hyperphagia and obesity immediately after weaning, and diabetes and its complications are found at a younger age in SDT-fa/fa rats than in SDT-+/+ rats [4,9,10,12]. However, blood pressure in SDT-fa/fa rats has not yet been examined.…”

Non-Obese Type 2 Diabetes Animals Models

“…Metabolic disorder in SDT fatty rats was obviously promoted as compared with SDT rats [104,105]. Serum glucose levels in SDT fatty rats of both sexes were elevated from 6 weeks, and lipid parameters such as serum triglyceride and total cholesterol levels in the rats were elevated from 4 weeks of age.…”