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Isoproterenol Induced Myocardial
Infarction in Guinea Pigs with Scurvy

Zeana, Corneliu; Laki, Desideriu;
Smaranda, Constantinescu.

Emergency Hospital Bucharest Romania

Background: Experimental myocardial infarction like lesions are obtained by injecting high isoproterenol doses in rat. Facing to stress rat is able to multiply by 10 to more than 30 its ascorbic acid synthesis. Man is entirely dependent of exogenous ascorbic acid. Rat is dissimilar to humans in this respect.

Objectives: To realize a new model of experimental myocardial infarction in an animal unable to synthesize ascorbic acid.

Material and Methods: 210 adult guinea pigs divided in lots: 1) control; 2) injected with different isoproterenol (isop) doses; 3) guinea pigs with scurvy; 4) guinea pigs with scurvy injected with isop.; 5) idem, one hour after magnesium ascorbate administration. Optical and electronic microscopy, myocardial adenosine triphosphate (ATP), serum LDH, cytochrome oxidize and succynate dehydrogenate in myocardial mitochondria homogenates, calcium and magnesium myocardial levels, ECG.

Results: Guinea pigs proved to be more sensitive to isop. than rats so that the isop. dose was reduced to 10 mg/kg (instead of 25-75 mg/kg in rats) in order to obtain an acceptable level of immediate mortality. Severe myocardial lesions were noted electron-microscopy in scurvy along with significant rise of serum LDH, depression of myocardial ATP, cytochrome oxidase and succynate dehydrogenate in mitochondria, accumulation of calcium and lowering of magnesium in myocardium.

In guinea pigs with scurvy isop. induced extremely severe morphological lesions accompanied by accentuation of metabolic abnormalities, reflecting massive myocardial necrosis. In this model, magnesium ascorbate proved to be very effective in myocardial protection.

Conclusions: Isop. induced myocardial infarction like lesions obtained in guinea pigs with scurvy. New experimental model.



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2nd Virtual Congress of Cardiology

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