Comparison of the effects of lead disodium ethylenediaminetetraacetate and lead acetate on hard tissues

Abstract

The present study is an attempt to define the effect of lead disodium ethylene-diaminetetraacetate (PbEDTA) on the hard tissues of rats. The effect of PbEDTA was compared with the effect of lead acetate (PbAc) given in dose equivalent to the lead content of the PbEDTA solution in vivo and in vitro . Concentrations of serum calcium and phosphorus increased 1 hr after the iv injection of PbAc (30 mg/kg) whereas those after PbEDTA (50 mg/kg) did not show any significant change in comparison with normal values. These changes were also shown for the in vitro experiment in which 100 mg of rat bone powder was shaken in 2 ml of buffered serum with 0.2 ml of each reagent (Pb: 600 μ g). Deposition of lead was observed histochemically in both dentine and bone after the intravenous injection of each reagent. Lead content of bone powder increased significantly after treatment with each reagent in vitro , in comparison with the normal content. These results suggest that, after the administration of PbEDTA, both PbEDTA itself and a portion of lead ion produced by the dissociation are deposited in the hard tissues in vivo .