Erick Valentino1,2, Ana Paula Silveira Leite1,2, Carina Guidi Pinto1,2, Felipe Cantore Tibúrcio1,2, Paula Aiello Tomé de Souza Castro3 and Selma Maria Michelin Matheus2*
1Graduate Program in Surgery and Translational Medicine, São Paulo State University, Brazil
2Department of Structural and Functional Biology, Institute of Biosciences, São Paulo State University, Brazil
3Department of Physical Therapy, Federal University of São Carlos, Brazil
Skeletal muscle aging is characterized by loss of muscle mass and function caused by a reduction systemic hormone. Physical exercises have beneficial effects in lean mass and may influence the Neuromuscular Junctions (NMJs). Anabolic androgenic steroids, such as Nandrolone Decanoate (ND), are widely used among athletes, but can cause a decrease of testosterone. The objective of this study was to evaluate the impacts of a supraphysiological dose of ND with or without physical exercises during youth on soleus muscle and their NMJs. Twenty 90-day-old male Sprague-Dawley rats were treated for 8 weeks and distributed into sedentary or exercised groups, with or without ND use (twice/week, 5 mg/kg, im.). Physical exercise was conducted by jumping in water three times per week. At the age of 300 days, muscles were collected, and the analyses were performed:
Morphological, morphometric, and ultrastructural analysis of muscle fibers and their NMJs; immunohistochemistry and morphometric analysis of fast- and slow- muscle fibers; and confocal microscopy for Acetylcholine Receptors (nAChRs). Results demonstrated that there was a weight decrease in the animals but not in the muscle that got ND. The morphology and morphometry of the NMJs remained steady, and regarding ultrastructure, the junctional folds were scarce. The animals that exercised had a pattern of nAChRs in continuous branches, and in sedentary groups, the "island" pattern was present. The pattern of slow- and fast-twitch muscle fibers remained stable in all groups. Central nuclei and focal areas of injury as well as myofibrillar disorganization were observed in the animals that got ND. Thus, the alterations observed in this study were consequences of the aging process and physical exercises performed in youth maintained the structural pattern of nAChRs that characterizes young animals. ND did not prevent morphological changes in the neuromuscular systems that are consequences of aging.
Aging; Nandrolone decanoate; Physical exercise; Neuromuscular junction
Valentino E, Leite APS, Pinto CG, Tibúrcio FC, de Souza Castro PAT, Matheus SMM. Physical Exercises during Youth Regardless of Nandrolone Decanoate Use Prevent Neuromuscular Morphological Alterations Caused by Aging. World J Phys Rehabil Med.
2021; 5(1): 1017..