Received March 22, 2006
Revised April 25, 2006
Accepted after revision July 27, 2006
Effect of swimming on myostatin expression in white and red gastrocnemius muscle and in cardiac muscle of the rats
Antonios Matsakas 1,
Cyrille Bozzo 1,
Nicola Cacciani 1,
Francesca Caliaro 1,
Carlo Reggiani 1,
Francesco Mascarello 1,
Marco Patruno 1*
1 University of Padua
* To whom correspondence should be addressed. E-mail: marco.pat{at}unipd.it.
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Abstract |
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The aim of this study was to test the hypothesis that swim training might differentially impact myostatin expression in skeletal muscles depending on fibre type composition and in cardiac muscle of the rat.
Myostatin expression was analysed by Real time PCR, Western blot and immuno-histochemistry in red deep portion (mainly composed of slow and 2A fibres) and in the superficial white (composed of fast 2X and 2B fibres) portion of the gastrocnemius muscle in adult male Wistar rats i) subjected to two consecutive swimming bouts for 3 hours, ii) subjected to an intensive swimming training for four weeks and iii) in control sedentary rats.
Myostatin mRNA content was in all cases higher in white than in red muscles. Two bouts of swimming did not alter myostatin expression, whereas swimming training for 4 weeks resulted in a significant reduction of myostatin mRNA contents, significant both in white and red muscles but more pronounced in white muscles. Western blot did not detect any change in the amount of myostatin protein. Immunohistochemistry showed that, in control rats, myostatin was localised in presumptive satellite cells of a few muscle fibres. After training the number of myostatin positive spots decreased significantly. Myostatin mRNA content in cardiac muscle was lower than in skeletal muscle and was significantly increased by swimming training.
In conclusion, the results obtained showed that intense training caused a decreased expression of myostatin mRNA in white and red skeletal muscles but determined an increase in cardiac muscle.
Key Words:
Exercise, Muscle, Muscle fibre
