CARDIOPROTECTIVE EFFECT OF VOLUNTARY PHYSICAL ACTIVITY ON CHANGES OF DOXORUBICIN-INDUCED CARDIAC MYOSIN HEAVY CHAIN EXPRESSION IN AGING MODEL RATS

Despite confirmed effectiveness of forced exercise training in reducing
doxorubicin-induced cardiotoxicity, the role of voluntary physical activity in reducing doxorubicininduced
cardiotoxicity, especially in the elderly, still has not been investigated properly. The aim of this
study was to investigate the protective effect of cardiac protection caused by voluntary physical activity
on myosin heavy chain gene (MyHC) expression changes induced by doxorubicin in the aging model
rats.
Materials & Methods: In this experimental study, after induction of aging, 24 twelve-week old male
rats with an average weight of 25025g received 100 mg/kg D-galactose solution for 9 weeks through
intraperitoneal injection. They were randomly divided into three groups: aging + saline (AS), aging +
doxorubicin (AD), and aging + doxorubicin + voluntary physical activity (ADWR). Voluntary physical
activity was carried out during the last 6 weeks of aging, on a running wheel.
In the last 15 days, 1 mg/kg doxorubicin and saline (cumulative dose of 15 mg/kg) was peritoneally
injected to the rats receiving doxorubicin and saline. Forty eight hours after the last injection of
doxorubicin, the left ventricle was isolated, and gene expression of cardiac myosin heavy chain was
measured using Real time - PCR.
Results: Doxorubicin increased beta myosin heavy chain gene expression and decreased alpha-cardiac
myosin heavy chain gene expression (MyHC) in the AD group. However, voluntary 6-week physical
activity decreased doxorubicin-induced changes in MyHC gene expression in the ADWR group.
Conclusion: Voluntary physical activity is a tool effective in reducing doxorubicin-induced
cardiotoxicity in the elderly.