Chinese Journal of Tissue Engineering Research ›› 2021, Vol. 25 ›› Issue (17): 2650-2656.doi: 10.3969/j.issn.2095-4344.3136

Previous Articles     Next Articles

An 8-week aerobic exercise improves obesity-induced myocardial fibrosis: role of nuclear factor-erythroid 2 p45-related factor 2 pathway

Zhang Lei, Yan Yu, Liu Yin, Xu Long, Yang Xinglei, Liu Yujia   

  1. School of Physical Education, Jiangsu Normal University, Xuzhou 221116, Jiangsu Province, China
  • Received:2020-04-16 Revised:2020-04-22 Accepted:2020-05-27 Online:2021-06-18 Published:2021-01-08
  • Contact: Liu Yujia, PhD, Lecturer, School of Physical Education, Jiangsu Normal University, Xuzhou 221116, Jiangsu Province, China
  • About author:Zhang Lei, School of Physical Education, Jiangsu Normal University, Xuzhou 221116, Jiangsu Province, China
  • Supported by:
    the Natural Science Foundation of Jiangsu Province, No. BK20190999 (to LYJ); the Natural Science Foundation of Jiangsu Provincial Universities, No. 18KJB180003 (to LYJ); the National University Student Innovation and Entrepreneurship Project, No. 201910320046 (to ZL)

Abstract: BACKGROUND: Obesity is a risk factor for myocardial fibrosis. Obesity-induced oxidative stress may be a potential cause of myocardial fibrosis. Nuclear factor-erythroid 2 p45-related factor 2 (Nrf2) is an important nuclear transcription factor that regulates the redox state in the body. Its expression and function can be improved by aerobic exercise training, and it is unclear whether aerobic exercise can improve obesity-induced myocardial fibrosis through Nrf2 pathway.
OBJECTIVE: To investigate the effects of 8-week aerobic exercise training on the regulation of myocardial fibrosis in obese rats
METHODS: Sixty 8-week-old male Sprague-Dawley rats were selected, of which 20 were fed with normal feed, and the remaining 40 were fed with high fat diet to induce obesity. Twenty obese rats were finally selected. Obese and normal rats were randomly divided into a normal control group, a normal exercise group, an obese control group, and an obese exercise, with 10 in each group. All rats were trained for 8 weeks on the treadmill platform, and the training plan was: 0°, 20 m/min, 60 min/d, 5 d/wk. All rats were anesthetized and sacrificed at 48 hours after the last exercise, and rat myocardium was taken. Sirius red staining was used to detect myocardial collagen levels. ELISA was used to detect myocardial malondialdehyde level. Western blot was used to determine the expression of type I, III collagen, matrix metalloproteinase 2 (MMP2), tissue inhibitor of matrix metalloproteinase (TIMP2), Nrf2 and antioxidant-related quinone oxidoreductase, heme oxygenase 1 and superoxide dismutase in the myocardium.  
RESULTS AND CONCLUSION: Obesity could induce myocardial fibrosis in rats, and the 8-week aerobic exercise training activated the Nrf2 level in the myocardium of obese rats, promote the expression of antioxidant enzymes heme oxygenase 1 and superoxide dismutase, downregulate the ratio of MMP2/TIMP2, reduce the content of myocardial type I collagen, reduce the myocardial collagen score, and thus improve obesity-induced myocardial fibrosis. However, the 8-week aerobic exercise training increased the protein expression of Nrf2 and quinone oxidoreductase of normal rats, while it did not affect the myocardial collagen content, myocardial collagen and MMP2/TIMP2 ratio.

Key words: obesity, myocardial fibrosis, aerobic exercise, heme oxygenase 1, factor, rat, experiment

CLC Number: