Avaliação comparativa entre dois modelos de indução química de diabetes mellitus tipo 1 em ratos Wistar

Abstract

Diabetes mellitus (DM) is an important public health problem not only due to its incidence, but also to its potential for morbidity and mortality. Animal models play an important role in understanding a natural history of the disease and other therapeutic alternatives that contribute to a reduction in the consequences associated with this disease. Chemical induction of DM has been widely used, with alloxan and streptozotocin (STZ) being the most important drugs. The objective of this study was to evaluate the efficacy between these drugs considering the relation between induction/mortality and clinical and histopathological changes. Intraperitoneal injection of alloxan induced 50% of the animals in the disease and 20% at death. Treatment with STZ took 90% of the animals to become diabetic and only 10% of failure, and no intraperitoneal injection was observed. The TALX group had mean water and feed intake of 209.6  5.7 mL and 43.5  3.7 g, respectively. For the TSTZ group, mean water and feed intake of 220.4  5.7 mL and 48.3  1.2 g were observed. The volume of urine excreted for the TALX and TSTZ groups was 144.4  5.9 mL and 156.7  5.5 mL, respectively. The mean weight loss between the first and last week of the experiment was 63.8  44.5 g for the TALX group and 59.9  36.1 g for the TSTZ group. In the weekly assessment of blood glucose for an increase of 434.4  133.6 mg/dL in the first week and 491.8  117.9 mg/dl in the fourth week for the TALX group and 402.2  32.7 mg/dL and 459.8  199.1 mg/dL for the TSTZ group. The histopathological analysis of the liver, kidneys and pancreas allowed an observation of organ changes in all diabetic animals. No histopathological changes were observed and in none of the clinical parameters of the control group. These results suggest that the chemical induction of DM is more satisfactory using STZ when compared to the use of alloxan in rats when kept in metabolic cages. Furthermore, it can be concluded that polyuria, polyphagia and polyuria were more pronounced in STZ-induced animals, and there were no significant differences in weight loss and fasting glycemia between the TALX and TSTZ groups.