Effect of 6 Weeks of Aerobic Training on TGF-Β1, Myostatin and Matrix Metalloproteinase 9 Genes Expression in the Tendon of Fast- and Slow-Twitch Muscles of Male Wistar Rats.

Background and Aim Tendon, like the skeletal muscle, exhibits mechanical and morphological adaptations resulted from exercise training; however, little is known about the basic cellular and molecular mechanisms that regulate these responses. The aim of the present study was therefore to investigate the effect of 6 weeks of aerobic training on the TGF-β1, myostatin and MMP9 mRNAs expression in the tendon of fast- and slow-twitch muscles. Methods & Materials For this purpose, 12 male Wistar rats at 8 weeks of age were randomly divided into two groups: experimental (n=6) and control (n=6). The exercise group performed aerobic training for 6 weeks, 5 sessions per week. Forty-eight hours after the last training session, all rats were sacrificed and the tendons of soleus and Extensor Digitorum Longus (EDL) muscles were extracted. Expression of TGF-β1, myostatin and MMP9 mRNAs were assayed using RealTime-PCR. Independent t-test was also used for statistical analysis. Ethical Considerations All stages of the study were conducted according to the ethical guidelines and authorization of Research Deputy of Islamic Azad University, Central Tehran Branch No. IR.IAU.PS.REC.1398.296. Results The results showed that the expression of TGF-β1 mRNA in EDL and soleus tendons significantly increased (P≤0.001), whereas the expression of myostatin in EDL tendon was significantly reduced (P≤ 0.001). Increased mRNA expression of MMP9 in the tendon of EDL and soleus muscles was not statistically significant (P>0.05). Conclusion It seems that aerobic exercise can modulate the expression of genes involved in the regulation of tendon collagen in a muscle type-dependent manner. [ABSTRACT FROM AUTHOR]