Expressão de miostatina, ActRIIB, ALK4 e folistatina em músculo esquelético e tecidos adiposos de ratos diabéticos submetidos ao exercício de natação

Abstract

Introduction: Myostatin (MSTN), a member of TGF-β family, is characterized as a negative regulator of muscle mass and is present in small quantities in adipose tissue. Accumulating evidences suggest its participation in energetic metabolism. Follistatin (FS) is a non-related protein which inhibits MSTN action. Objective: The objective of this study was to determine the influence of exercise in the expression of MSTN, its receptors (ActRIIB and ALK4), and FS in muscle (white gastrocnemius) and fat (epidydimal, mesenteric, subcutaneous and brow adipose tissue BAT) in streptozotocin-induced diabetic rats. Material and Methods: Control and diabetic animals were randomly assigned to a swimming training group (EC and ED) or a sedentary group (SC and SD). Exercising animals swam for 4 weeks. MSTN, ActRIIB, ALK4 and FS mRNA was quantified by real time RT-PCR and protein expression by Western blotting. Results: Blood glucose was significantly lower in ED than in SD. MSTN and FS mRNA expression increased in SD compared to SC in muscle and subcutaneous fat. The expression of ActRIIB mRNA increased in SD compared to SC in muscle, mesenteric fat and BAT. Expression of ALK4 mRNA increased in SD compared to SC only in BAT. The protein expression of MSTN increased in muscle of the DS when compared to CS. The expression of N-terminal propeptide from the MSTN increased in DS compared to CS in mesenteric fat and TAM. After training, MSTN and ActRIIB were lower in EC compared to SC in BAT. MSTN increased in mesenteric fat and FS mRNA expression decreased in muscle, mesenteric, subcutaneous fat and BAT in ED when compared with SD. ALK4 mRNA expression was lower in BAT when compared to ED with SD. The expression of LAP of MSTN decreased in muscle and mesenteric fat f DE compared to DS. Conclusion: The results indicate that MSTN, its receptors and FS expression changes in both muscle and adipose tissues in diabetic rats and that their expression can be modulated by exercise in Diabetes Mellitus.