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Cardiac lesions and their reversibility after long term administration of methamphetamine
M N Islam1, H Kuroki, B Hongcheng
1Department of Legal Medicine, Osaka University Medical School, Japan.
Abstract:
In order to clarify the effect of methamphetamine (MA) on myocardium, histological, immunohistochemical and electron microscopic changes in the myocardium of rats were examined following daily intraperitoneal administration of MA at a dose of 1 mg per kg body weight for 4, 8, and 12 weeks before sacrifice. Normal saline (NS) was similarly injected for the same period before sacrifice to constitute a control group. Light microscopic changes found in the myocardium of the MA-treated group included atrophy, hypertrophy, patchy cellular infiltration, eosinophilic degeneration and disarray, edema myolysis, fibrosis, and the appearance of vacuoles. Ultrastructurally, nuclei and normal mitochondria had various shapes and there were dilated T tubules and sarcoplasmic reticulum, the accumulation of glycogen granules and fat droplets. Intra- and extra-cellular edema and intramyocytic vacuoles were often found. Withdrawal of MA at the twelfth week in another group of rats evidenced gradual recovery of the myocardial changes, commencing at 3 weeks after withdrawal. Optimism is therefore generated about the possibility of the affected hearts in MA-abuse patients returning towards the normal state if they give up the drug.
Insights
Methamphetamine (MA) causes significant myocardial damage in rats, including cellular changes and fibrosis. However, these heart injuries show gradual recovery after MA withdrawal, suggesting potential for recovery in human MA abusers who cease drug use.
Area of Science:
- Cardiovascular Pathology
- Toxicology
- Histopathology
Background:
- Methamphetamine (MA) abuse is a growing public health concern.
- The cardiac effects of chronic MA use are not fully understood.
- Understanding MA's impact on the myocardium is crucial for clinical management.
Purpose of the Study:
- To investigate the histological, immunohistochemical, and ultrastructural effects of chronic MA administration on rat myocardium.
- To assess the reversibility of MA-induced myocardial changes after drug withdrawal.
Main Methods:
- Rats received daily intraperitoneal injections of MA (1 mg/kg) or normal saline for 4, 8, or 12 weeks.
- Histological and electron microscopic examinations were performed on myocardial tissues.
- A separate group underwent MA withdrawal at 12 weeks to evaluate recovery.
Main Results:
- MA treatment led to significant myocardial alterations, including atrophy, hypertrophy, cellular infiltration, degeneration, edema, myolysis, fibrosis, and vacuole formation.
- Ultrastructural analysis revealed nuclear and mitochondrial abnormalities, dilated T tubules and sarcoplasmic reticulum, and accumulation of glycogen and fat.
- Myocardial changes began to gradually recover 3 weeks after MA withdrawal.
Conclusions:
- Chronic methamphetamine administration induces substantial myocardial damage in rats.
- These cardiac injuries are partially reversible upon cessation of MA use.
- This suggests that abstinence from MA may allow for recovery of heart function in human abusers.