Abstract
Introduction:
Doxorubicin (DOX) is a widely used chemotherapeutic agent with known cardiotoxic properties, while calorie restriction (CR) and exercise have well-documented cardioprotective effects. No studies have investigated the effects of CR alone or the combined effects of CR and exercise on DOX cardiotoxicity.
Methods:
Rats were divided into 4 groups based on their food intake (ad libitum or CR) and activity (sedentary or voluntary wheel running [WR]). After completing a 16-week treatment, animals received either DOX (15 mg/kg) or saline (SAL) and cardiac function was measured 5 days after treatment. Chromatography was used to quantify left ventricular DOX accumulation.
Results:
Left ventricular developed pressure (LVDP), end systolic pressure (ESP), and left ventricular maximal rate of pressure development (dP/dtmax) were significantly higher in the CR + DOX group when compared with DOX. Fractional shortening, LVDP, ESP, dP/dtmax, and dP/dtmin were significantly higher in the CR + WR + DOX group compared with the DOX group. In addition, the CR + WR + DOX group showed significantly higher LVDP and ESP compared with the WR + DOX group. DOX accumulation in the heart was 5-fold lower ( P < .05) in the CR + WR + DOX group compared with the DOX group.
Conclusion:
This is the first study to demonstrate that CR can reduce cardiac DOX accumulation, and confirms the protective role of CR against DOX-induced cardiac dysfunction. Our data also show that combining a known cardioprotective intervention, exercise training, with CR results in additive benefits in the protection against DOX cardiotoxicity.
Keywords:
calorie restriction; cardiotoxicity; doxorubicin; exercise.