Developing a rat model of dilated cardiomyopathy with improved survival

Area of Science:

• Cardiology
• Pharmacology
• Toxicology

Background:

• Doxorubicin (Dox) is a widely used chemotherapy agent.
• Dox-induced cardiotoxicity is a significant clinical concern.
• Optimizing Dox administration may mitigate cardiac damage.

Purpose of the Study:

• To compare continuous infusion versus intermittent bolus doxorubicin (Dox) administration.
• To establish a rat model of doxorubicin-induced dilated cardiomyopathy with improved survival.
• To evaluate the impact of different Dox dosing regimens on cardiac function and survival.

Main Methods:

• 150 Sprague-Dawley rats were divided into control, Dox 1 (1 mg/kg twice weekly), and Dox 2 (2 mg/kg once weekly) groups.
• Echocardiography assessed cardiac function and chamber dimensions.
• Biomarkers (BNP, CRP, Caspase-3), histology, and 18F-fluoro-deoxyglucose-positron emission tomography (18FDG-PET) evaluated myocardial damage and viability.
• Serum creatinine and aspartate aminotransferase monitored kidney and liver function.

Main Results:

• Mortality rates were significantly higher in the Dox 2 group (48%) compared to the Dox 1 group (22%).
• Both Dox regimens induced significant chamber dilatation, reduced cardiac function, and increased cardiac stress biomarkers.
• Histology and 18FDG-PET revealed decreased myocardial viability, necrosis, and fibrosis in Dox-treated rats.
• Dox 2 group showed significantly higher serum creatinine and aspartate aminotransferase levels.

Conclusions:

• Both doxorubicin administration protocols induce dilated cardiomyopathy in rats.
• Lower, more frequent doxorubicin doses (Dox 1) significantly reduce mortality compared to higher, less frequent doses (Dox 2).
• Optimizing doxorubicin administration strategies is crucial for improving patient survival and managing cardiotoxicity.