O RATO COMO MODELO EXPERIMENTAL DO DIABETES - ESTUDO CLINICO-LABORATORIAL

In this study, 90 Wistar rats were used. They were equally divided into three experimental groups - control group (CG), diabetic group (DG) and treated diabetic group (TG). The analyzed parameters were clinical (behavior, activity, general aspect, weight, water ingestion and diuresis) and biochemical (fasting glycemia and urinary glycosis). The diabetes was induced by alloxan and, then, treated with insulin associated to oral hypoglycemic (acarbosis). Observations were made at 5 experimental moments, as it follows: 1, 3, 6, 9, and 12 months after the diabetes induction. The results were submitted to variance analysis, with 5% of significance level. The DG presented lower weight and higher diuresis level than the CG and TG. The water ingestion of the CG was similar to TG. The glycemia levels were higher in DG than in CG, at every experimental moment. The TG, however, presented glycemia similar to the CG, except for the dosages at 3, and 9 months. They urinary glycosis of the DG and TG were similar between themselves, but higher than the one of the CG.

Effects of protein malnutrition on glucose tolerance in rats with alloxan-induced diabetes

Protein-calorie malnutrition produces glucose intolerance and reduced insulin release in response to glucose. Rats adapted to low- or high-protein diets show an increased resistance to the diabetogenic action of a single dose of streptozotocin or alloxan. To determine the effects of dietary protein level on pancreatic function, we measured serum glucose levels under basal conditions and during the oral glucose tolerance test (GTT) performed before and after a single dose of alloxan administered to rats fed a 25% or a 6% protein diet for a period of 8 weeks. The incidence of mild hyperglycemia (serum glucose > 250 mg/dl) was greater among the rats fed the 25% protein diet (81%) than among those fed the 6% protein diet (42%). During the GTT performed before alloxan administration the serum glucose levels of the rats fed the 6% protein diet were not found to be significantly different from those of rats fed the 25% protein diet. During the GTT performed after alloxan injection all rats showed intolerance to the substrate (serum glucose > 160 mg/dl 120 min after glucose administration) regardless of whether basal serum glucose was normal or high. In summary, alloxan was less effective in producing basal hyperglycemia in the rats fed the 6% protein diet than in those fed the 25% protein diet but caused glucose intolerance during the oral GTT in both groups. Thus, it seems that feeding a 6% protein diet to rats offers only partial protection against the toxic effects of alloxan.

Estudo do extrato de Ginkgo biloba na prevenção de malformações em recémnascidos de ratas diabéticas

The pregnant women presenting Diabetes mellitus develop metabolic alterations, that may cause damage to the fetal well-being and provoke anomalies and/or malformations. The antioxidant treatment has improved the embryonic development from streptozotocin diabetic rats. Several studies have shown that a Gingko biloba extract presents antioxidant effects and, in the present study, one of the G. biloba extract formulations was used (EGb761) - Tebonin (200 mg/Kg/day), given to the diabetic pregnant female rats. The aim was to evaluate the effect of the EGb761 treatment on the of anomalies and/ or malformations incidence of the offspring. Diabetes was induced in female rats using streptozotocin in a dose of 40 mg/kg. The rats were mated, and the pregnant animals were divided in two groups: Control (water) and experimental (G. biloba). At day 21 of pregnancy, the rats were killed, and their fetuses were analyzed and processed for anomalies and/or malformations incidence. The results demonstrated that control and experimental groups presented no external anomalies and malformations; increased incidence of skeletal anomalies and of visceral malformations, and lower rate of visceral anomalies and skeletal malformations. These data confirm no statistical difference and, therefore, EGb761 treatment did not cause changes. Thus, a dose of 200 mg/Kg/day of a Gingko biloba extract given during the pregnancy rat was ineffective in the prevention of the anomalies and/or malformations related to the diabetes.