Mitigating Doxorubicin-Induced Cardiotoxicity through Quercetin Intervention: An Experimental Study in Rats

Abstract

Doxorubicin (DOX) is an effective anticancer drug, but its use is limited by dose-dependent heart toxicity. Quercetin is a natural antioxidant frequently studied for its beneficial properties. Moreover, a wide range of dietary supplements are available for human use. This in vivo study aimed to explore the potential cardioprotective effects of quercetin in chronic DOX treatment. A total of 32 Wistar rats were randomly divided into four groups: control, DOX, DOX/Q-50, and DOX/Q-100, treated with saline, 2.5 mg/kg body-weight DOX, 2.5 mg/kg body-weight DOX + 50 mg quercetin, and 2.5 mg/kg body-weight DOX + 100 mg quercetin, respectively, for two weeks. Rats were monitored using cardiac ultrasound (US) and markers for cardiac injury. Oxidative damage and ultrastructural changes in the heart were investigated. Chronic DOX treatment led to a decline in cardiac function and elevated values of NT pro-BNP, troponin I, and CK-MB. Quercetin treatment slightly improved certain US parameters, and normalized serum NT pro-BNP levels. Furthermore, DOX-induced SOD1 depletion with consequent Nrf2 activation and DNA damage as shown by an increase in γH2AX and 8HOdG. Quercetin treatment alleviated these alterations. Oral administration of quercetin alleviated serum markers associated with DOX-induced cardiotoxicity. Furthermore, it exhibited a favorable impact on the cardiac US parameters. This suggests that quercetin may have potential cardioprotective properties.

Keywords: DNA damage; antineoplastic agents; antioxidants; cardiotoxicity; doxorubicin; microscopy; oxidative stress; quercetin; reactive oxygen species.

Figure 1

Study design and workflow. A total of 32 Wistar rats were divided into 4 groups: control, receiving i.p. injections of 0.9% saline solution; DOX, receiving i.p. injections with 2.5 mg/kg body-weight doxorubicin; DOX/Q-50, receiving i.p. injections with 2.5 mg/kg body-weight doxorubicin and 50 mk/kg/day quercetin orally; DOX/Q-100, receiving i.p. injections with 2.5 mg/kg body-weight doxorubicin and 100 mk/kg/day quercetin orally. DOX: doxorubicin; i.p.: intraperitoneal; Q: quercetin; NT-proBNP: natriuretic peptide; TnI: troponin I; LDH: lactate dehydrogenase; CK: creatine kinase; CK-MB: creatine kinase isoenzyme MB; SOD: superoxide dismutase.

Figure 2

Oral administration of quercetin alleviates serum markers of cardiac injury and US parameters in an in vivo model of DOX-induced chronic cardiotoxicity. (A) NT-proBNP, CK-MB, TnI were significantly increased by multiple DOX doses in Wistar rats. Quercetin administration lowered the levels of these markers in a dose-dependent manner. (B) DOX altered the cardiac echocardiography parameters while quercetin improved cardiac function. DOX: doxorubicin; Q: quercetin; IVSd: interventricular septal thickness in diastole; IVSs: interventricular septal thickness in systole; LVPWs: LV posterior wall thickness in diastole; LVPWd: LV posterior wall thickness in systole; LVEDD: LV end-diastolic dimension; LVESD: LV end-systolic dimension; LVEF: LV ejection fraction; FS: fractional shortening. * p < 0.05; ** p < 0.01; *** p < 0.001.

Figure 3

Network pharmacology analysis. (A). Protein–protein interaction map of the putative proteins commonly involved in quercetin effects and cardiotoxicity. (B). Barplot showing top 20 significant pathways from the functional enrichment.

Figure 4

Oxidative damage in DOX and quercetin-treated rats. Alterations in the antioxidant defense system (A), DNA damage (B), and apoptosis (C) associated with DOX and quercetin treatments. Chronic DOX treatment induced an increase in Nrf-2 levels together with a depletion of SOD-1 enzyme indicating an alteration in ROS homeostasis. Quercetin treatment successfully reversed these changes. DOX: doxorubicin; Q: quercetin; Nrf2: Nuclear factor erythroid 2-related factor 2; SOD1: superoxide dismutase 1; γH2AX: H2A histone family member X; 8-OHdG: 8-Hydroxy-2-Deoxyguanosine. * p < 0.05; ** p < 0.01.

Figure 5

TEM images showing cardiomyocytes with normal ultrastructure in control group (A,B), and with modified ultrastructure in DOX group (C,D). Rarefaction and lesions of myofibrils; enlargement of sarcoplasmic reticulum, alteration of mitochondria, and presence of secondary lysosomes. am: altered mitochondria; g: glycogen; l2: secondary lysosomes; m: mitochondria; mf: myofibrils, sr: sarcoplasmic reticulum; *: lysed myofibrils.

Figure 6

TEM images showing cardiomyocytes with slightly modified ultrastructure in DOX/Q50 group (A,B). Proliferated sarcoplasmic reticulum, rarefied myofibrils, numerous granules of glycogen and altered mitochondria, and cardiomyocytes with nearly normal ultrastructure in DOX/Q100 group (C,D), Normal aspect of myofibrils; rare, dilated profiles of sarcoplasmic reticulum; presence of large granules of glycogen; rare, altered mitochondria; and rare secondary lysosomes. am: altered mitochondria; g: glycogen; l2: secondary lysosomes; m: mitochondria; mf: myofibrils, sr: sarcoplasmic reticulum.

Figure 7

Proposed mechanisms of action of quercetin treatment in chronic DOX-induced cardiotoxicity. Red arrows indicate the damaging effects of DOX which are alleviated by quercetin administration (green blunt arrows).