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Updated: Sep 10, 2025
A Doxorubicin-Induced Murine Model of Dilated Cardiomyopathy In Vivo
Published on: May 16, 2020
Methylene Blue Mitigates Doxorubicin-Induced Cardiotoxicity via KEAP1/NRF2/GPX-4/Caspase3 Modulation
Shaimaa G Ibrahim1, Ahmed M Abu-Dief2,3, Amany M Gad4,5
1Department of Pharmacology and Toxicology, Faculty of Pharmacy, October 6 University, Giza 12585, Egypt.
Abstract:
Doxorubicin (Dox) is a potent anthracycline antitumor drug whose clinical utility is significantly restricted by its dose-dependent, cumulative cardiotoxicity, driven by increased oxidative stress, impaired antioxidant defenses, and apoptosis-mediated cardiomyocyte loss. Methylene blue (MB), a phenothiazine derivative with well-documented redox-modulating properties, is being explored as a viable cardioprotective agent due to its antioxidant and anti-apoptotic effects. This study evaluated the protective role of MB against Dox-induced cardiotoxicity in rats by examining its impact on oxidative stress markers (Kelch-like ECH-associated protein 1; KEAP1, nuclear factor erythroid 2-related factor 2; NRF2, Glutathione peroxidase 4; GPX-4, 8-hydroxy-2'-deoxyguanosine; 8-OHdG), neurohormonal indicators (noradrenaline), cardiac injury biomarkers (troponin I), and apoptotic mediators (p53, Caspase-3). Forty male albino rats were divided equally into four groups: control, Dox (15 mg/kg, i.p.), MB alone (4 mg/kg/day, p.o. for 7 days), and Dox plus MB. Dox administration significantly increased serum troponin I and noradrenaline levels, elevated cardiac KEAP1 and 8-OHdG, and reduced NFE2L2, NRF2, and GPX-4 expression. It also upregulated p53 and Caspase-3 and caused marked myocardial degeneration, necrosis, and inflammatory infiltration. MB co-treatment significantly reduced troponin I and noradrenaline levels, restored KEAP1/NFE2L2 (NRF2)/GPX-4 pathway balance, decreased oxidative DNA damage, and attenuated p53 and Caspase-3 activation, preserving myocardial architecture with minimal inflammatory changes. These findings demonstrate that MB confers potent cardioprotection against Dox-induced cardiac injury by enhancing antioxidant defenses, limiting oxidative DNA damage, suppressing apoptosis, and normalizing neurohormonal imbalance, suggesting its promise as an adjunctive strategy to mitigate anthracycline-associated cardiotoxicity.
Insights
Methylene blue (MB) protects against doxorubicin (Dox)-induced heart damage by boosting antioxidant defenses and reducing oxidative stress and apoptosis. This suggests MB as a promising adjunctive therapy to prevent Dox cardiotoxicity.
Area of Science:
- Cardiology
- Pharmacology
- Toxicology
Background:
- Doxorubicin (Dox) is a vital chemotherapy drug, but its use is limited by dose-dependent cardiotoxicity.
- This cardiotoxicity is characterized by oxidative stress, reduced antioxidant capacity, and cardiomyocyte apoptosis.
- Methylene blue (MB) is being investigated for its redox-modulating and cardioprotective properties.
Purpose of the Study:
- To evaluate the cardioprotective effects of Methylene blue (MB) against Doxorubicin (Dox)-induced cardiotoxicity in a rat model.
- To investigate MB's impact on oxidative stress, apoptosis, and cardiac injury markers.
Main Methods:
- Forty male rats were divided into four groups: control, Dox, MB alone, and Dox plus MB.
- Doxorubicin was administered at 15 mg/kg, and Methylene blue at 4 mg/kg/day for 7 days.
- Key markers assessed included troponin I, noradrenaline, KEAP1, NRF2, GPX-4, 8-OHdG, p53, and Caspase-3.
Main Results:
- Dox administration significantly elevated cardiac injury markers (troponin I, noradrenaline), oxidative stress (KEAP1, 8-OHdG), and apoptosis (p53, Caspase-3), while decreasing antioxidant markers (NRF2, GPX-4).
- MB co-treatment significantly reduced troponin I and noradrenaline, restored the KEAP1/NRF2/GPX-4 pathway, decreased oxidative DNA damage, and attenuated apoptosis.
- Histopathological examination showed MB preserved myocardial architecture and reduced inflammation in Dox-treated rats.
Conclusions:
- Methylene blue demonstrates significant cardioprotection against Dox-induced cardiotoxicity.
- MB enhances antioxidant defenses, reduces oxidative DNA damage, suppresses apoptosis, and normalizes neurohormonal imbalance.
- MB shows promise as an adjunctive therapy to mitigate anthracycline-associated cardiotoxicity.
