PAX7 and MyoD Proteins Expression in Response to Eccentric and Concentric Resistance Exercise in Active Young Men

Document Type : Original Article


1 Department of Physical Education and Sport Sciences, Science and Research Branch, Islamic Azad University, Tehran, Iran

2 Exercise Physiology Research Center, Life Style Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran


Objective: Satellite cells play an important role in muscle regeneration, which this process can be affected by different
genes including PAX7 and MyoD. Exercise training known as an important strategy for mediating the satellite cell’s
function. Therefore, the main purpose of the present study is to investigate the changes in PAX7 and MyoD protein
expression in response to eccentric and concentric resistance exercise in healthy young men.
Materials and Methods: In this semi-experimental and cross-sectional study, 10 healthy men (age range 18-30 years
old) participated. They were randomly divided into two equal groups (n=5) to perform one of two high-intensity eccentric
or concentric knee extensions muscle contraction protocols. The contractions included a maximum of 12 sets of 10
repetitions, with a 30 second rest time interval between sets. PAX7 and MyoD protein expression was assessed using
Immunohistochemistry analysis from the Vastus Lateralis muscle needle biopsy samples that have been taken 24
hours before and 3 to 4 hours after the end of the exercise protocol.
Results: We observed that the PAX7 protein expression level increased significantly after eccentric (47.75%) and
concentric (39.21%) (P=0.01) intervention. While, the MyoD protein expression level reduced (38.14%) significantly
following acute eccentric resistance exercise (P=0.01).
Conclusion: It seems that eccentric or concentric muscular contraction modulates the expression of PAX7 and MyoD
protein expression in the skeletal muscle, with further effects observed in eccentric resistance exercise.


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