Padronização de um modelo experimental de diabetes mellitus tipo 1 e avaliação de parâmetros de estresse oxidativo em jundiá (Rhamdia quelen)

Abstract

Diabetes mellitus (DM) is a syndrome caused by insulin production deficiency, or by its incapacity to execute its functions. Hyperglycemia, a characteristic of DM, causes many metabolic disorders such as weight loss, fatigue, vasculopathy and neuropathy. For induction of type 1 DM, streptozotocin (STZ) is used in order to destroy the insulin productions pancreas beta cells. Oxidative stress (OS) is directly related to pathways that generate complications caused by DM. So, its evaluation is essential to check possible treatments. Thus, the use of animals in vivo is the best way to study drugs and other alternative ways to treating this syndrome. The jundiá (Rhamdia quelen) is an endemic fish from southern Brazil, and its main characteristics are good adaptation to cold weather, easy reproduction and handling. Based on the above, this study aimed to create an alternative experimental model for the study of biochemical changes induced by DM. For this, we obtained 60 animals. Was used 20 fish to conduct a dose-response curve to STZ. With this result, the dose of 200 mg/kg was selected as the most effective. In the standardization of the DM model, we used 30 animals, which were divided into control group and treated with STZ (200 mg/kg) group, followed by 30 days. Biometric analyses was done every two weeks. At the end of treatment, animals were euthanized their tissues was removed (brain, muscle, liver, kidney and blood) for analysis. We evaluated the glucose levels, triglycerides, the sulfhydryl groups (-SH), thiobarbituric acid reactive species (TBARS), and the δ-ALA-D enzyme activity. At the end of the experiment, there was no significant hyperglycemic state in animals. However, elevated levels of lipid peroxidation were observed in muscle, -SH total in the liver, δ-ALA-D enzyme activity in the brain, and a decrease in GSH levels in the muscle, indicating that animals treated with STZ undergone OS. In conclusion, OS bio-indicators show that oxidative damage was performed in tissues. However, more studies are needed to assess whether there is a relationship with prior hyperglycemic state or whether it is an isolated effect of stressor STZ.