الفهرس 
DoxorubicinOnly 14 pages are availabe for public view
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Abstract
Background: Long-term exercise could confer protection against Doxorubicin-induced cardiotoxicity and cardiomyopathy, yet, the effect of short-term exercise just prior to exposure to doxorubicin (Dox) is still unclear. Aim: To investigate the effect of short-term exercise on cardiac dysfunction induced by Dox treatment, also, to evaluate heat shock protein (HSP20) and oxidative status of cardiac tissue to clarify possible underlying mechanism (s) of such effect. Materials and Methods: Sixty nine female albino rats were assigned into 4 groups: group 1: control (sedentary rats, n=17), group 2: Dox (rats received single intraperitoneal injection of Dox in a dose of 20 mg/kg, and studied 24 hours later, n=18), group 3: Exc (rats swim exercised 1 hour/day for 3 days, n=16), group 4: Exc +Dox ( rats exercised as in group 3 and received Dox injection as in group 2 on the third day and studied 24 hours later, n=18). Rats were subjected to recording of the ECG, measurement of arterial blood pressure, echocardiograghy, analysis of serum parameters of SGOT, LDH, CPK-MB, troponin I (cTnI) and evaluation of total antioxidant capacity, malondialdehyde (MDA) and Hsp20 in the cardiac tissue. Results: Compared to the control, Dox-treated rats showed significant prolongation of the observed QT (QTo) and corrected QT (QTc) interval, with insignificant depression of the R voltage and the elevation of systolic (SBP), diastolic (DBP), mean (MAP) blood pressures were statistically insignificant. These changes were accompanied by significant elevation of serum SGOT and significant increases in cardiac tissue MDA and Hsp20. Also, compared to the control, rats exposed to 3 days exercise just before Dox injection (Exc+Dox) showed significant prolongation of both QTo and the QTc even more than Dox group. However, the depression of the R voltage and the elevation of the SBP, DBP, and MAP become statistically significant compared to the control. These changes were associated with significant increase in SGOT together with insignificant changes in MDA and Hsp20. However, compared to Dox group, the Exc+Dox demonstrated significant prolongation in both QTo and the QTc, significant reduction in both the ejection fraction and the fraction of shortening together with significant reductions in MDA and HSP20. Conclusion: Short-term swim exercise training just prior to doxorubicin exposure is risky and makes the heart more predisposed to arrhythmia despite of the relative improvement in cardiac oxidative status.