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Cancer is the second leading cause of death in the United States and has become a health problem worldwide. The reported incidence of new cancer cases is estimated at 19.3 million, with a mortality rate of 10 million in the world in 2020. There are several therapeutic approaches for cancer, including chemotherapy. Chemotherapy is consuming anti-neoplastic drugs, alone or in combination. However, it causes damages to the normal cells and has many side effects. Cardiac complications are common side effects of some chemotherapy agents. Cardiac myocytes are potentially more susceptible to the long-term adverse effects of chemotherapy agents due to the less regeneration ability in cardiac cells. Moreover, heart muscle dysfunction (cardiomyopathy) and cardiovascular complications may occur in cancer survivors even a year after chemotherapy or radiation therapy and influence their quality of life. Anthracyclines are commonly used in chemotherapy; especially doxorubicin is the most widely used drug of this family. Doxorubicin is an effective anti-malignant agent prescribed for the treatment of some solid tumors (e.g. ovary, breast, and gastrointestinal cancers). Doxorubicin can cause several side effects, ranging from cancer treatment’s common side effects such as fever, nausea, and vomiting to lethal cardiac side effects. Assumed that doxorubicin has many therapeutic and cytotoxic mechanisms, cardiotoxicity induced by doxorubicin is very common and there is no reliable treatment for this problem. The cardiac side effects of doxorubicin during a chemotherapy regimen can be acute, chronic, or even gradually progressive and persistent after the termination of doxorubicin therapy. In patients undergoing doxorubicin therapy, reported symptoms are cardiac rhythm and blood pressure changes, pericarditis, myocarditis, cardiomyopathy, and congestive heart failure. The pathophysiology of doxorubicin-induced cardiotoxicity is very wide. Disruption of normal mitochondrial function, decreased amount of antioxidant factors, production of reactive oxygen species (ROS), an imbalance in calcium hemostasis, activation of inflammatory cytokines, targeting topoisomerase-IIβ (Top2b), and induced DNA damage are associated with doxorubicin-induced cardiotoxicity. Increased doxorubicin in mitochondria activates the redox cycle that ultimately leads to the production of reactive oxygen species in both normal and tumor cells. The present review aims to investigate the cardiotoxic mechanisms of doxorubicin and explain different types of doxorubicin-induced cardiotoxicity.

The clinical use of doxorubicin as a potent chemotherapeutic agent is limited due to its dose-dependent cardiotoxicity. Oxidative stress and inflammatory pathways have a pivotal role in the doxorubicin-induced cardiotoxicity. SumatriptanHT)1B/1D agonist that mainly used to relieve migraine pain, has suggested exerting protective effects in numerous pathological conditions through anti-inflammatory properties. The aim of the present study was to investigate the effects of sumatriptan on doxorubicin-induced cardiotoxicity and the contribution of anti-inflammation and anti-oxidative responses. Cardiotoxicity was induced by administration of doxorubicin 3 times a week (2.5 mg/kg i.p) for 2 consecutive weeks on male rats. The animals were divided in to the four group including: Control, Sumatriptan (0.1 mg/kg) received group, Doxorubicin received group, and Doxorubicin+ Sumatriptan (0.1 mg/kg) received group .Sumatriptan was administered 30 min before every injection of doxorubicin. On the last day of the second week, the body weight, mortality rate, electrocardiogram (ECG) and histopathological changes, inotropic and biochemical factors were evaluated. The loss of body weight, mortality rate, ECG parameters, reduction of papillary muscle contractility force as well as histopathological scores following administration of doxorubicin indicated the severe cardiac damage. However, treatment with sumatriptan inhibited the functional and structural impairment induced by doxorubicin. In addition, sumatriptan could significantly reduce cardiac tissue levels of malondialdehyde (MDA) and tumor necrosis factor-alpha (TNF-α) which was increased in the doxorubicin-treated rats. This study illustrated protective effects of sumatriptan on decreasing doxorubicin-induced cardiac toxicity and mortality rate in part through inhibition of inflammatory and oxidative stress pathways.

Postconditioning is a simple and safe strategy for cardioprotection and infarct size limitation. Our previous study showed that oxytocin (OT) exerts postconditioning effect on ischemic/reperfused isolated rat heart. The aim of this study was to investigate the involvement of OT receptor, mitochondrial ATP-sensitive potassium channel (mKATP), nitric oxide (NO) and cyclooxygenase (COX) pathways in OT postconditioning. Isolated rat hearts were divided into10 groups and underwent 30 min of regional ischemia followed by 120 min of reperfusion (n =6). In I/R (ischemia/reperfusion) group, ischemia and reperfusion were induced without any treatment. In OT group, oxytocin was perfused 5 min prior to beginning of reperfusion for 25 min. In groups 3-6, atosiban (oxytocin receptor blocker), L-NAME (N-Nitro-L-Arginine Methyl Ester, non-specific nitric oxide synthase inhibitor), 5-HD (5-hydroxydecanoate, mKATP inhibitor) and indomethacin (cyclooxygenase inhibitor) were infused prior to oxytocin administration. In others, he mentioned inhibitors were perfused prior to ischemia without oxytocin infusion. Infarct size, ventricular hemodynamic, coronary effluent, malondialdehyde (MDA) and lactate dehydrogenase (LDH) were measured at the end of reperfusion. OT perfusion significantly reduced infarct size, MDA and LDH in comparison with IR group. Atosiban, 5HD, L-NAME and indomethacin abolished the postconditioning effect of OT. Perfusion of the inhibitors alone prior to ischemia had no effect on infarct size, hemodynamic parameters, coronaryeffluent and biochemical markers as compared with I/R group. In conclusion, this study indicates that postconditioning effects of OT are mediated by activation of mKATP and production of NO and Prostaglandins (PGs).