Effect of Swimming Exercise on Irisin Levels in Streptozotocin Induced Type 1 and Type 2 Diabetes Mellitus in Rats, MOUSTAFA H. ABD EL-SALAM and MARWA A. HABIB
Abstract
Background: Irisin is a recently discovered cytokine formed and secreted as a cleaved fragment of fibronectin type Ш domain containing 5 (FNDC5). It is mainly released by skeletal muscle and since its discovery it was suggested to be responsible for the beneficial effects of exercise on metabolism and several researches has addressed its relation to diabetes mellitus and metabolic disorders. The present study aims to investigate effect of exercise on the regulation of the circulating levels of irisin in Туре 1 and 2 streptozotocin diabetic rats.
Methods: 48 Wistar rats were divided into three main groups: Control Non-Diabetic group (CND), Туре 1 Diabetes Mellitus group (TI DM) and Type 2 Diabetes Mellitus group (Т2DМ). Each group was further subdivided into two equal subgroups (sedentary and chronic exercise). Chronic exercise rats performed swimming exercise for one hour/day, 5 days/ week for 8 weeks. At the end of the study period all animals were anaesthetized then decapitated to obtain blood samples. Blood samples were analyzed for insulin, glucose, Glycosylated hemoglobin (HbA1c) Total Cholesterol (ТС), High Density Lipoprotein (HDL), Triglycerides (TGs), and irisin levels. Low and very Low-Density Lipoproteins (LDL & VLDL), Homeostatic models for insulin resistance (HOMA-IR) and B cell function (ЛОМА-B) were calculated.
Results: Ти) induced a significant increase in circulating irisin level (p<0.041) while Т2D was accompanied with a significant (p<0.000) reduction of circulating serum irisin levels. Chronic exercjse for eight weeks significantly increased circulating irisin levels in control, type 2 diabetes mellitus however, it had no significant effect in type 1 diabetes mellitus groups. In diabetic groups irisin was significantly correlated with blood glucose, insulin HОМA-IR, НОМА 4, НЬАlс, TC, VLDL and TGs while in exercise groups it showed significant correlation with blood glucose, HOMA-IR, ТС, VLDL and TGS.