en فیزیولوژی ورزشی Sport Physiology تحقيقي Original Paper <strong>Background and objectives:</strong> Osteoarthritis is one of the most common arthritic diseases and a main cause of pain and disability. Simultaneous downexpression of <em>paired box 7</em> (<em>Pax7</em>) and <em>myogenin</em> genes, as indicators of satellite cells activation is evident in osteoarthritis. This study assessed effects of an exercise training course and stem cell injection on the expression of <em>Pax7</em> and <em>myogenin </em>in gastrocnemius muscle of rats with arthritis.<span dir="RTL"></span><br> <strong>Methods:</strong> Thirty five male rats aged 6&ndash;8 weeks and weighing 250&ndash;300 g were divided into five groups: control, patient, exercise, mesenchymal stem cell (MSC), and exercise+MSC. Osteoarthritis was induced in rats by surgery. The training program consisted of 30 minutes of running on a non-slip treadmill at a speed of 16 m/min. The rats were injected with 1&times;10⁶ cells/kg MSC. The expression of <em>Pax7</em> and <em>m</em><em>yogenin</em> was measured by real&ndash;time PCR. Data were analysed with SPSS (version 23) using one-way analysis of variance. &nbsp;<br> <strong>Results:</strong> Both <em>Pax7</em> and <em>myogenin </em>were significantly overexpressed in the exercise+MSC group compared to the patient group (P<0.001).<br> <strong>Conclusion:</strong> The combination of MSC therapy and training had more positive effects on <em>Pax7</em> and <em>myogenin</em> expression compared to training and MSC therapy alone. Exercise, Stem cells, Pax7, Myogenin, Arthritis 41 47 http://mlj.goums.ac.ir/browse.php?a_code=A-10-233-7&slc_lang=en&sid=1 hassan rasouli seiedhassanrasooli@yahoo.com 100319475328460018362 100319475328460018362 No Exercise Physiology Department, Sari Branch, Islamic Azad University, Sari, Iran parvin farzanegi parvin.farzanegi@gmail.com 100319475328460018363 100319475328460018363 Yes Exercise Physiology Department, Sari Branch, Islamic Azad University, Sari, Iran hajar abbaszadeh 100319475328460018364 100319475328460018364 No Exercise Physiology Department, Sari Branch, Islamic Azad University, Sari, Iran