Avaliação da netose como moduladora dos efeitos cardiovasculares induzidos pelo exercício físico crônico
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Data
2019-03-01
Autores
Claro, Renan Floret Turini [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
A prática do exercício físico regular agrega inúmeros benefícios à saúde, principalmente ao sistema cardiovascular, em que se observa por exemplo o aumento da função contrátil do músculo cardíaco. Porém, a intensidade do exercício pode atuar como um estressor múltiplo, atingindo diretamente o metabolismo energético, oxidativo, neuro-hormonal, térmico e mecânico. Essas alterações resultam na mobilização e ativação de leucócitos, proteínas de fase aguda, bem como alterações na via fibrinolítica e cascata de coagulação. Em resposta às agressões causadas por infecções, respostas inflamatórias e estímulos fisiológicos como o exercício físico agudo, os neutrófilos realizam processo de morte celular chamado netose. Recentemente, a netose foi descrita, a princípio como terceira estratégia (juntamente da fagocitose e degranulação) de morte e controle de patógenos. Sua principal formação são as NETs (neutrophil extracellular traps), que são estruturas em formatos de fios, compostas por material citoplasmático e nuclear que são lançadas de maneira coordenada e programada para o meio extracelular. Considerando que as NETs podem estar envolvidas em efeitos deletérios e fisiológicos em diferentes sistemas, recentemente, trabalho pioneiro indicou que o exercício físico agudo extenuante de natação foi acompanhado por aumento de NETs. No entanto, os efeitos do exercício crônico e agudo em outra modalidade, com utilização de diferentes intensidades no processo da netose ainda não são conhecidos. Assim, este trabalho utilizou quatro protocolos de prescrição de corrida em esteira rolante em ratos, sendo eles: exercício físico agudo (AGUDO), exercício aeróbio (AERO), exercício intervalado de alta intensidade ou High Intensity Interval Training (HIIT), sobretreinamento ou overtraining (OVER) e grupo controle sedentário (SED). O tempo de exposição ao exercício físico foi de três meses para grupos submetidos ao processo de treinamento, com frequência de sessões de cinco vezes por semana. Os controles de intensidade do treinamento foram realizados por meio da velocidade correspondente ao percentual do consume máximo de oxigênio. Nas análises das medidas corporais dos animais, foi encontrada diferença significativa no peso final entre os grupos HIIT e AERO. Em relação ao consumo máximo de oxigênio no final do processo de treinamento, o grupo submetido ao treinamento intervalado de alta intensidade foi maior em comparação aos grupos AERO, AGUDO e SED. Na quantificação das NETs, não foram encontradas diferenças significativas entre os grupos. Como conclusão, o trabalho apresentou alterações de condicionamento físico dos animais condizentes com as expectativas do processo de treinamento, inclusive com modificações funcionais cardíacas. Porém, a prática da corrida, tanto em efeitos agudos como crônicos, não demonstrou diferença na produção de NETs.
The practice of regular physical exercise adds numerous health benefits, mainly to the cardiovascular system, in which, for example, there is an increase in the contractile function of the heart muscle. However, exercise intensity can act as a multiple stressor, directly affecting energy, oxidative, neurohormonal, thermal and mechanical metabolism. These changes result in mobilization and activation of leukocytes, acute phase proteins, as well as changes in the fibrinolytic pathway and coagulation cascade. In response to the aggressions caused by infections, inflammatory responses and physiological stimuli such as acute physical exercise, neutrophils perform the process of cell death called netosis. Recently, netose has been described, initially as a third strategy (along with phagocytosis and degranulation) of death and pathogen control. Its main formation is the NETs (neutrophil extracellular traps), which are structures in yarn formats, composed of cytoplasmic and nuclear material that are released in a coordinated and programmed way into the extracellular environment. Considering that NETs may be involved in deleterious and physiological effects in different systems, recently, pioneering work indicated that strenuous acute physical exercise of swimming was accompanied by increased NETs. However, the effects of chronic and acute exercise in another modality, using different intensities in the netose process, are not yet known. Thus, this work utilized four treadmill running prescription protocols in rats: acute physical exercise (ACUTE), aerobic exercise (AERO), high intensity interval exercise or High Intensity Interval Training (HIIT), overtraining or overtraining (OVER) and sedentary control group (SED). The physical exercise exposure time was three months for groups submitted to the training process, with frequency of sessions five times a week. The training intensity controls were performed by means of the velocity corresponding to the percentage of the maximum oxygen consumption. In the analysis of the body measurements of the animals, a significant difference was found in the final weight between the HIIT and AERO groups. Regarding the maximum oxygen consumption at the end of the training process, the group submitted to the high intensity interval training was larger in comparison to the AERO, ACUTE and SED groups. In the quantification of NETs, no significant differences were found between groups. In conclusion, the work presented alterations in the physical condition of the animals according to the expectations of the training process, including with cardiac functional modifications. However, the practice of running, in both acute and chronic effects, showed no difference in the production of NETs.
The practice of regular physical exercise adds numerous health benefits, mainly to the cardiovascular system, in which, for example, there is an increase in the contractile function of the heart muscle. However, exercise intensity can act as a multiple stressor, directly affecting energy, oxidative, neurohormonal, thermal and mechanical metabolism. These changes result in mobilization and activation of leukocytes, acute phase proteins, as well as changes in the fibrinolytic pathway and coagulation cascade. In response to the aggressions caused by infections, inflammatory responses and physiological stimuli such as acute physical exercise, neutrophils perform the process of cell death called netosis. Recently, netose has been described, initially as a third strategy (along with phagocytosis and degranulation) of death and pathogen control. Its main formation is the NETs (neutrophil extracellular traps), which are structures in yarn formats, composed of cytoplasmic and nuclear material that are released in a coordinated and programmed way into the extracellular environment. Considering that NETs may be involved in deleterious and physiological effects in different systems, recently, pioneering work indicated that strenuous acute physical exercise of swimming was accompanied by increased NETs. However, the effects of chronic and acute exercise in another modality, using different intensities in the netose process, are not yet known. Thus, this work utilized four treadmill running prescription protocols in rats: acute physical exercise (ACUTE), aerobic exercise (AERO), high intensity interval exercise or High Intensity Interval Training (HIIT), overtraining or overtraining (OVER) and sedentary control group (SED). The physical exercise exposure time was three months for groups submitted to the training process, with frequency of sessions five times a week. The training intensity controls were performed by means of the velocity corresponding to the percentage of the maximum oxygen consumption. In the analysis of the body measurements of the animals, a significant difference was found in the final weight between the HIIT and AERO groups. Regarding the maximum oxygen consumption at the end of the training process, the group submitted to the high intensity interval training was larger in comparison to the AERO, ACUTE and SED groups. In the quantification of NETs, no significant differences were found between groups. In conclusion, the work presented alterations in the physical condition of the animals according to the expectations of the training process, including with cardiac functional modifications. However, the practice of running, in both acute and chronic effects, showed no difference in the production of NETs.
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Palavras-chave
Exercício físico, Netose, Remodelação cardíaca