Background & Aims: Despite confirmed effectiveness of forced exercise training in reducing doxorubicin-induced cardiotoxicity, the role of voluntary physical activity in reducing doxorubicin-induced 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.

SOURCE: URMIA MED J 2016: 26(10): 901 ISSN: 1027-3727