Effectiveness of sodium 4,5-dihydroxybenzene-1,3-disulfonate (Tiron) in protecting against uranium-induced developmental toxicity in mice.

The effect of Tiron (sodium 4,5-dihydroxybenzene-1,3-disulfonate), a chelating agent used in the treatment of experimental poisoning by a number of heavy metals, on uranium-induced developmental toxicity was evaluated in Swiss mice. A series of four Tiron injections was administered intraperitoneally to pregnant mice immediately after a single subcutaneous injection of 4 mg/kg of uranyl acetate dihydrate given on day 10 of gestation and at 24, 48, and 72 h thereafter. Controls received 0.9% saline with or without uranyl acetate. Tiron effectiveness was assessed at 500, 1000 and 1500 mg/kg per day. Amelioration by Tiron of uranium-induced embryolethality was not noted at the two lower doses. The percentage of dead and resorbed fetuses in the Tiron-treated groups was not statistically different from that in the positive control group. However, treatment at 1500 mg/kg per day showed isolated protective effects against uranium fetotoxicity, such as that evidenced by the lack of differences in fetal body weight between this group and the uranium-untreated group, as well as by a decrease in the number of skeletal defects. According to these results, the ability of Tiron to protect the developing mouse fetus against uranium-induced developmental toxicity offers only modest encouragement with regard to its possible therapeutic potential for pregnant women exposed to this metal.