Cardiac Effects of Treadmill Running at Different Intensities in a Rat Model

Purpose: In this study, we investigated the effect of treadmill exercise training on cardiac hypertrophy, collagen deposition, echo parameters and serum levels of cardiac troponin I (cTnI) in rats, and how they differ with various exercise intensities, hence exploring potential signal transduction.M...

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Autores principales:	Zhipeng Yan, Ni Zeng, Jieting Li, Tao Liao, Guoxin Ni
Formato:	article
Lenguaje:	EN
Publicado:	Frontiers Media S.A. 2021
Materias:	exercise treadmill running cardiac structure and function cardiac hypertrophy ERK signaling pathway Physiology QP1-981
Acceso en línea:	https://doaj.org/article/ef32326b2734492bb1c2a7eaf7f5bc01
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spelling	oai:doaj.org-article:ef32326b2734492bb1c2a7eaf7f5bc012021-12-01T13:18:33ZCardiac Effects of Treadmill Running at Different Intensities in a Rat Model1664-042X10.3389/fphys.2021.774681https://doaj.org/article/ef32326b2734492bb1c2a7eaf7f5bc012021-11-01T00:00:00Zhttps://www.frontiersin.org/articles/10.3389/fphys.2021.774681/fullhttps://doaj.org/toc/1664-042XPurpose: In this study, we investigated the effect of treadmill exercise training on cardiac hypertrophy, collagen deposition, echo parameters and serum levels of cardiac troponin I (cTnI) in rats, and how they differ with various exercise intensities, hence exploring potential signal transduction.Methods: Male Sprague-Dawley rats were randomly divided into sedentary (SED), low-intensity running (LIR), medium-intensity running (MIR), and high-intensity running (HIR) groups. Each exercise group had 3 subgroups that were sacrificed for cardiac tissue analyses at 1, 4, and 8 weeks, respectively, and all rats participated in a daily 1 h treadmill routine 5 days per week. Echocardiographic measurements were performed 24 h after the last exercise session. Additionally, myocardium samples and blood were collected for histological and biochemical examinations. Changes in the extracellular signal-regulated kinases 1/2 (ERK1/2) signal pathway were detected by Western blotting.Results: After a week of running, ventricular myocyte size and the phosphorylation of ERK1/2 increased in the HIR group, while left ventricular (LV) diastolic diameter values and LV relative wall thickness increased in the LIR and MIR groups. In addition, we observed heart enlargement, cTnI decrease, and ERK1/2 signal activation in each of the exercise groups after 4 weeks of running. However, the HIR group displayed substantial rupture and increased fibrosis in myocardial tissue. In addition, compared with the LIR and MIR groups, 8 weeks of HIR resulted in structural damage, fiber deposition, and increased cTnI. However, there was no difference in the activation of ERK1/2 signaling between the exercise and SED groups.Conclusion: The effect of running on cardiac hypertrophy was intensity dependent. In contrast to LIR and MIR, the cardiac hypertrophy induced by 8 weeks of HIR was characterized by potential cardiomyocyte injury, which increased the risk of pathological development. Furthermore, the ERK signaling pathway was mainly involved in the compensatory hypertrophy process of the myocardium in the early stage of exercise and was positively correlated with exercise load. However, long-term exercise may attenuate ERK signaling activation.Zhipeng YanNi ZengJieting LiTao LiaoGuoxin NiFrontiers Media S.A.articleexercisetreadmill runningcardiac structure and functioncardiac hypertrophyERK signaling pathwayPhysiologyQP1-981ENFrontiers in Physiology, Vol 12 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	exercise treadmill running cardiac structure and function cardiac hypertrophy ERK signaling pathway Physiology QP1-981
spellingShingle	exercise treadmill running cardiac structure and function cardiac hypertrophy ERK signaling pathway Physiology QP1-981 Zhipeng Yan Ni Zeng Jieting Li Tao Liao Guoxin Ni Cardiac Effects of Treadmill Running at Different Intensities in a Rat Model
description	Purpose: In this study, we investigated the effect of treadmill exercise training on cardiac hypertrophy, collagen deposition, echo parameters and serum levels of cardiac troponin I (cTnI) in rats, and how they differ with various exercise intensities, hence exploring potential signal transduction.Methods: Male Sprague-Dawley rats were randomly divided into sedentary (SED), low-intensity running (LIR), medium-intensity running (MIR), and high-intensity running (HIR) groups. Each exercise group had 3 subgroups that were sacrificed for cardiac tissue analyses at 1, 4, and 8 weeks, respectively, and all rats participated in a daily 1 h treadmill routine 5 days per week. Echocardiographic measurements were performed 24 h after the last exercise session. Additionally, myocardium samples and blood were collected for histological and biochemical examinations. Changes in the extracellular signal-regulated kinases 1/2 (ERK1/2) signal pathway were detected by Western blotting.Results: After a week of running, ventricular myocyte size and the phosphorylation of ERK1/2 increased in the HIR group, while left ventricular (LV) diastolic diameter values and LV relative wall thickness increased in the LIR and MIR groups. In addition, we observed heart enlargement, cTnI decrease, and ERK1/2 signal activation in each of the exercise groups after 4 weeks of running. However, the HIR group displayed substantial rupture and increased fibrosis in myocardial tissue. In addition, compared with the LIR and MIR groups, 8 weeks of HIR resulted in structural damage, fiber deposition, and increased cTnI. However, there was no difference in the activation of ERK1/2 signaling between the exercise and SED groups.Conclusion: The effect of running on cardiac hypertrophy was intensity dependent. In contrast to LIR and MIR, the cardiac hypertrophy induced by 8 weeks of HIR was characterized by potential cardiomyocyte injury, which increased the risk of pathological development. Furthermore, the ERK signaling pathway was mainly involved in the compensatory hypertrophy process of the myocardium in the early stage of exercise and was positively correlated with exercise load. However, long-term exercise may attenuate ERK signaling activation.
format	article
author	Zhipeng Yan Ni Zeng Jieting Li Tao Liao Guoxin Ni
author_facet	Zhipeng Yan Ni Zeng Jieting Li Tao Liao Guoxin Ni
author_sort	Zhipeng Yan
title	Cardiac Effects of Treadmill Running at Different Intensities in a Rat Model
title_short	Cardiac Effects of Treadmill Running at Different Intensities in a Rat Model
title_full	Cardiac Effects of Treadmill Running at Different Intensities in a Rat Model
title_fullStr	Cardiac Effects of Treadmill Running at Different Intensities in a Rat Model
title_full_unstemmed	Cardiac Effects of Treadmill Running at Different Intensities in a Rat Model
title_sort	cardiac effects of treadmill running at different intensities in a rat model
publisher	Frontiers Media S.A.
publishDate	2021
url	https://doaj.org/article/ef32326b2734492bb1c2a7eaf7f5bc01
work_keys_str_mv	AT zhipengyan cardiaceffectsoftreadmillrunningatdifferentintensitiesinaratmodel AT nizeng cardiaceffectsoftreadmillrunningatdifferentintensitiesinaratmodel AT jietingli cardiaceffectsoftreadmillrunningatdifferentintensitiesinaratmodel AT taoliao cardiaceffectsoftreadmillrunningatdifferentintensitiesinaratmodel AT guoxinni cardiaceffectsoftreadmillrunningatdifferentintensitiesinaratmodel
_version_	1718405149850861568

Cardiac Effects of Treadmill Running at Different Intensities in a Rat Model

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