Compared effects of high oral Mg supplements and of EDTA chelating agent on chronic lead intoxication in rabbits.

Our previous experiments showed that excessive oral Mg intake has beneficial effects in chronic Pb poisoning, inducing decrease of Pb body burden and its increased elimination via urine. The aim of this work was to investigate and to compare the effect of Mg on urinary Pb elimination with the effect of calcium-disodium edetate (CaNa2EDTA)--chelating agent currently used in therapy of chronic Pb intoxication. Besides, under the same experimental conditions, biochemical parameters protoporphyrin IX (ppIX), zinc protoporphyrin (Znpp) and delta-aminolevulinic acid (ALA) were determined. Experiments were carried out on rabbits previously intoxicated for 4 weeks with 20 mg Pb/kg b.w. per day. After the period of intoxication, one group of animals was given per os, for 28 days, 40 mg Mg/kg, the other one was i.v. treated for 7 days with 15 mg CaNa2EDTA/kg (therapeutic doses), while the third one (rabbits without therapy) served as a control. During the period of detoxication, lead was determined in blood and urine samples, and ppIX and Znpp were determined in blood and ALA in urine. Results suggest that oral treatment with magnesium, although inducing later Pb elimination than EDTA, has even better effect on investigated biochemical parameters than chelating therapy.