Search

Background: Cardiotoxicity is the main complication of adriamycin (ADR), which is a widely used chemotherapeutic agent., Objective: To examine the potential cardioprotective effect of melatonin (MEL) on acute ADR cardiotoxicity in a rat model., Methods: Cardioprotection was assessed on the basis of myocardial lipid peroxidation and ultrastructure. Rats were given MEL at a daily dose of 5 mg/kg and ADR 15 mg/kg, intraperitoneally. The MEL-1 group rats received one dose and the MEL-7 group rats six daily doses of MEL and were sacrificed at the end of one and seven days, respectively. Rats in the ADR-1 and ADR-7 groups were each given a single dose of ADR, and were then sacrificed 24 h and seven days later, respectively. The MEL+ADR-1 group rats received one dose each of ADR and MEL simultaneously and were sacrificed 24 h later. The MEL+ADR-7 group received a single dose of ADR plus a daily MEL dose for six consecutive days, and were sacrificed seven days after the ADR injection., Results: Lipid peroxidation products were elevated in both ADR-1 and ADR-7 groups, and this elevation was significantly inhibited by MEL treatment. Electron microscopy confirmed that ADR was positively cardiotoxic after one and seven days of exposure. The extent of ADR-induced myocardial damage was markedly reduced when MEL was combined with ADR (MEL+ADR-1 and MEL+ADR-7)., Conclusion: The results suggest that MEL is highly efficacious at reducing the acute cardiotoxic effects of high dose ADR, and that it acts by preventing lipid peroxidation.