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Ultrastructural features of Adriamycin-induced skeletal and cardiac muscle toxicity
Abstract:
In this study, the authors examined the effect of the anti-tumor agent Adriamycin, a known cardiotoxin, on mouse heart, diaphragm, and gastrocnemius muscle. Using an established model of Adriamycin cardiac toxicity, they found that 4 days after the intraperitoneal injection of 20 mg/kg of Adriamycin, characteristic heart lesions, including vacuolation of the sarcoplasmic reticulum, interstitial edema, and mitochondrial degeneration, were demonstrated in all treated animals. Furthermore, similar, but much more severe, myocyte damage was demonstrated in the diaphragm; muscle toxicity followed a decreasing gradient of injury from the peritoneal to the thoracic surface of the tissue. On the other hand, treatment with Adriamycin resulted in an increase in the size and number of lipid droplets in the red fibers of the gastrocnemius muscle without any other ultrastructural evidence of drug-induced damage to myocytes. An examination of the pharmacokinetics and metabolism of Adriamycin after intraperitoneal treatment revealed that relative drug levels in muscle (diaphragm much greater than heart much greater than gastrocnemius) paralleled the degree of ultrastructural damage observed. This study indicates that treatment with Adriamycin can produce significant injury to non-cardiac muscle in a fashion that strongly resembles the characteristic pattern of Adriamycin-related damage to the heart, and that the degree of myocyte damage is apparently dependent upon the Adriamycin concentration in the tissue.
Insights
Adriamycin, an anti-tumor drug, causes significant muscle injury beyond the heart. This study reveals Adriamycin-induced damage in diaphragm and gastrocnemius muscles, correlating with drug concentration.
Area of Science:
- Pharmacology
- Toxicology
- Muscle Biology
Background:
- Adriamycin (doxorubicin) is a widely used chemotherapy agent with known cardiotoxicity.
- The precise mechanisms and extent of Adriamycin's effects on non-cardiac muscles are not fully understood.
Purpose of the Study:
- To investigate the impact of Adriamycin on mouse heart, diaphragm, and gastrocnemius muscle.
- To compare the ultrastructural damage and Adriamycin concentration across these tissues.
Main Methods:
- Mice were administered intraperitoneal Adriamycin (20 mg/kg).
- Cardiac and muscle tissues were analyzed for ultrastructural changes 4 days post-injection.
- Adriamycin pharmacokinetics and tissue concentrations were determined.
Main Results:
- Adriamycin induced characteristic cardiac lesions (vacuolation, edema, mitochondrial degeneration).
- Diaphragm muscle exhibited severe myocyte damage, while gastrocnemius showed increased lipid droplets in red fibers.
- Tissue Adriamycin levels correlated with the observed myocyte damage (diaphragm > heart > gastrocnemius).
Conclusions:
- Adriamycin causes significant injury to non-cardiac muscles, mirroring cardiac damage patterns.
- The severity of Adriamycin-induced myocyte damage is dependent on tissue drug concentration.