Atividade antihiperglicêmica e antioxidante da lectina de Bryothamnion seaforthii em ratos com diabetes induzido por estreptozotocina

Abstract

Diabetes mellitus (DM) is a chronic disease characterized by metabolic disorder of multiple etiologies, which occurs when the pancreas does not produce enough insulin or when the organism cannot effectively use the insulin produced, causing systemic hyperglycemia. The cause of diabetes is associated with a combination of dysfunction of pancreatic β-cells and insulin resistance, because the insulin produced is not capable of providing adequate peripheral glucose uptake. Approximately 7% of the world population lives with the disease and 90% of the cases are type 2 diabetes. Diabetes associated with hyperlipidemia may occur and generate increased production of free radicals, causing oxidative stress, which in turn causes endothelial dysfunction. Since the complexity of the DM, more studies are needed to provide alternative therapies for their treatment. Lectins have the peculiar property of binding to carbohydrates and display intrinsic role in cell communication, featuring a variety of biological effects, such as anti-inflammatory, pro-healing, anti-cancer, antiviral and antioxidant activities. This study aimed to evaluate the antihyperglycemic, antilipidemic and antioxidant activities of the lectin isolated from Bryothamnion seaforthii (BSL) thorough an in vivo study. For this evaluation, diabetes mellitus type 2 was induced in Wistar rats using streptozotocin and nicotinamide. The effectiveness and efficiency of the treatment were evaluated from serum collections at 0, 30, 60, 90 and 120 days after confirmation of hyperglycemia with serum assessment of fasting glucose, total cholesterol, triglycerides, evaluation of the enzymes glutathione peroxidase, catalase, superoxide dismutase, and determination of the insulin resistance by HOMA-IR (homeostasis model assessment for insulin resistance) and HOMA β (homeostasis model assessment e-cell function). In the study, it was observed that the groups treated with BSL were significantly reduced regarding the amount of fasting glucose, total cholesterol and triglycerides, as well as significantly increased the glutathione peroxidase activity. Superoxide dismutase difference was not observed with regard to catalase. Finally, regarding the assessments of HOMA-IR and HOMA-β levels, it was observed that BSL administration decreased insulin resistance and hypersecretion. In conclusion, these data suggest that BSL promotes hypoglycemic and hypolipidemic effect, and reduce insulin resistance as well as improve the function of β cells, also working improving the enzymatic activity in the oxidative stress caused by DM2.