Os efeitos da atividade física na remodelação óssea

Abstract

Bone is a dynamic tissue, developed and adapted by hormones, cytokines and mechanical stimuli, such as physical activity. The bone undergoes changes, even after the end of skeletal growth, comprising the remodeling process, that is a balance between apposition and bone reabsorption. In this context, the maintenance of bone mineral density (BMD) is very important for the prevention of metabolic bone diseases, such as osteoporosis, which is characterized by a marked decrease in BMD. Studies indicate that physical activity is positively related to BMD, being an important factor for its maintenance. Among these studies, some use force training as an intervention, in an attempt to increase the BMD of individuals submitted to this type of physical activity. At the cellular level, the process of remodeling induced by overload in physical activity, seems to be performed by the action of osteocytes, which act as mechanical receptors of the applied stress, and release a chemical stimulating factor of the proliferation of osteoblasts in the stressed place. This study aimed to evaluate the effect of physical activity on bone remodeling. For this purpose, information was searched in the databases of CAPES, MEDLINE, LILACS and in the SciELO virtual library, selecting papers published in national and international periodicals between 1999 and 2016. The descriptors of subjects used were: "physical activity "," Bone remodeling "," bone mineral density ", using the intersection of sets. Although some results are contradictory, the literature does not question the beneficial effects of physical activity on bone tissue, both in healthy individuals, and in the prevention and treatment of Osteoporosis. The mechanisms by which physical activity stimulates osteoblastic differentiation from bone marrow stromal cells should be better elucidated so that more appropriate therapies can be developed and used in the treatment of individuals with some metabolic bone disease. K E Y W O R D SMotor activity, Bone remodeling, Bone density R E S U M OO osso é um tecido dinâmico, desenvolvido e adaptado por hormônios, citocinas e estímulos mecânicos, como a atividade física. Ele sofre alterações, mesmo após o final do crescimento do esqueleto, compreendendo o processo de remodelação, ou seja, um equilíbrio entre a posição e reabsorção óssea. Nesse contexto, a manutenção da densidade mineral óssea (DMO) é muito importante para a prevenção de doenças ósseas metabólicas, como a osteoporose, a qual é caracterizada por uma diminuição acentuada da DMO. Estudos indicam que a atividade física está positivamente relacionada com a DMO, sendo um importante fator para sua manutenção. Dentre estes estudos, alguns utilizam o treinamento de força como intervenção, na tentativa de aumentar a DMO de indivíduos submetidos a esse tipo de atividade física. Em nível celular, o processo de remodelação, induzido pela sobrecarga, como na atividade física, parece ser realizado pela ação dos osteócitos, que atuam como receptores mecânicos do estresse aplicado e liberam um fa...