Effect of Exercise Training and Adropin Treatment on Thyroid and Testicular Function Changes in Obese Type 2 Diabetic Rats

Abstract

Background: Type 2 diabetes mellitus (T2DM) and thyroid dysfunctions are commonly observed concomitant endocrinopathies that have a common pathogenesis of insulin resistance. Also, adropin is a metabolic hormone that is secreted by many structures in the body. On the other hand, moderate exercise training was recorded to combat changes that occurred with obesity. But, the available information about the effect of type 2 diabetes mellitus on testicular function was contradictory and a scarce data was available on the effect of exercise training and adropin treatment on both thyroid and testicular functions in obese type 2 diabetic rats.Aim: This study investigated thyroid and testicular function changes occurred in obese type 2 diabetic rats and explored the effect of moderate exercise training and adropin treatment.Materials and Methods: Rats in this 10 weeks' study were divided randomly into two main groups, lean non-diabetic (were fed on ordinary chow) and obese diabetic [were fed on high fat and received streptozotocin (35 mg/kg) at the start of the 5th week]. Each main group was subdivided into sedentary, exercised and adropin treated subgroups. For the last 5 weeks of the study, rats in the exercised subgroups were exposed to a moderate swimming exercise protocol, while those in the adropin treated subgroups were administered adropin daily (2.1 μg/kg).Results: Obese diabetic groups had a significant increase in the final body weight, weight difference, body mass index (BMI), serum levels of [glucose, insulin, triglycerides (TG), total cholesterol (TC), low density lipoprotein (LDL), tumor necrosis factor alpha (TNFα), malondialdehyde (MDA) and thyroid stimulating hormone (TSH)] and value of homeostasis model assessment of insulin resistance index (HOMA-IR), with a significant decrease in serum [adropin, high-density lipoprotein (HDL), superoxide dismutase (SOD), thyroxine (T4), triiodothyronine (T3), follicle stimulating hormone (FSH), luteinizing hormone (LH) and testosterone] and epididymal sperm [count, motility and deformity] in comparison with the lean non-diabetic groups. Also, within the obese diabetic groups, serum adropin was negatively associated with weight difference, BMI, serum (glucose, TC, TNFα and TSH) and HOMA-IR, but it was