[Comparative study on myocardial damage in irradiated for a long time and nonirradiated rats after administration of FCOL].

The trials were made to assess the effect of FCOL (9-alpha-fluorocortisol + Na2HPO4) and the effect of K and Mg asparaginates and their mixtures on the modifications of Ca2+, Na+, and K+ ions and of the K/Na ratio in the myocardium of rats not irradiated or submitted to permanent whole-body irradiation (gamma irradiation with 0.57 Gy per day during 25 days, total accumulated dose 14.25 Gy; the trials were performed 25 days after the irradiation). The totality of reversible and irreversible functional modifications of the myocardium, expressed by the quantitative assessment of the K/Na ratio and the concentration of Ca2+ ions, was evaluated in order to determine the cardiotoxicity or cardioprotection. It was demonstrated that irradiation alone causes a slight irreversible modification in the myocardium which is not found in non-irradiated rats. FCOL itself increases the rate of Ca2+ and Na+ ions in irradiated and non-irradiated rats, but does not influence the quantity of K+ ions. Severe irreversible myocardial damages are caused by FCOL, but these damages are considerably lower in irradiated rats. Neither in irradiated nor in non-irradiated rats, the isomers of Mg asparaginate show any protective action against the cardiotoxic effect of FCOL. The isomers of K asparaginate, also combined with Mg asparaginates, as well as the preparation Inzolen exert a demonstrable protective effect against myocardial ion modifications following to application of FCOL. The protection is more efficient in irradiated rats.