Chinese Journal of Tissue Engineering Research ›› 2020, Vol. 24 ›› Issue (8): 1243-1248.doi: 10.3969/j.issn.2095-4344.2466

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Effect of exercise-induced muscle damage on desmin aggregates

Gao Yang1, Bai Shengchao2, Chen Shengju1, Wang Ruiyuan1, Li Junping1   

  1. 1Sport Science College, Beijing Sport University, Beijing 100084, China; 2Department of Physical Education, Nanjing University of Science and Technology, Nanjing 210094, Jiangsu Province, China
  • Received:2019-07-12 Revised:2019-07-13 Accepted:2019-08-20 Online:2020-03-18 Published:2020-01-21
  • Contact: Li Junping, PhD, Associate professor, Sport Science College, Beijing Sport University, Beijing 100084, China
  • About author:Gao Yang, Doctoral candidate, Sport Science College, Beijing Sport University, Beijing 100084, China
  • Supported by:
     the National Natural Science Foundation of China, No. 31471133; the Fundamental Research Funds for the Central Universities, No. 2019PT013

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Abstract:

BACKGROUND: Protein degradation is the main reason of exercise induced muscle damage (EIMD). High-intensity exercise may lead to the misfolding of proteins and form aggregates, which is harmful to the ultrastructure of skeleton muscle.

OBJECTIVE: To determine the formation and role of protein aggregate (especially the desmin aggregate) in EIMD.

METHODS: Sixty-four adult male Sprague-Dawley rats (purchased from Beijing Vital River Laboratory Animal Technology Co., Ltd., China) were randomly divided into eight groups (control, post-exercise 0, 3, 6, 12, 24, 48, and 72 hours, eight rats in each). A damage model was established by downhill running (-16°, 16 m/min, 90 minutes). All rats were then killed at corresponding time points to take the soleus as specimen. Severity of damage was observed histologically under a transmission electron microscope. Expression of ubiquitin in the insoluble protein of soleus muscle was detected using western blot, and expression of desmin aggregates was observed by immunofluorescence double labeling. All experimental procedures were approved by the Beijing Sport University Institutional Review Board.

RESULTS AND CONCLUSION: (1) After a large-load eccentric exercise, the sarcomere of the soleus muscle was widened, the Z-line was broken, and the myofibril was broken and distorted, all of which was most serious at 12 hours after exercise, and recovered completely at 72 hours after exercise. (2) Western blot results indicated that the expression of ubiquitin in the skeletal muscle increased first and then decreased after a large-load eccentric exercise. The expression peaked at 12 hours after exercise and returned to normal at 72 hours after exercise. (3)Overall expression of desmin aggregates significantly raised (P < 0.01) instantly when the EIMD occurred. It reached the peak at 12 hours after exercise, then reduced somewhat (P < 0.01) at 24 and 48 hours, and finally recovered at 72 hours. (4)These findings indicate that desmin aggregation may be one of the causes of EIMD.

Key words:

exercise, skeletal muscle, muscle damage, protein aggregates, desmin, desmin aggregates, ubiquitin, tissue engineering

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