Effects of meso-2,3-dimercaptosuccinic acid (DMSA) on methyl mercury-induced teratogenesis in mice

Methyl mercury has been reported to be embryotoxic and teratogenic in numerous systems such as fish, birds, and mammals. meso-2,3-Dimercaptosuccinic acid (DMSA) has been useful for prevention and treatment of mercury poisoning. In this study, the protective activity of DMSA on methyl mercury-induced embryo/fetotoxicity was evaluated in mice. A series of four DMSA injections was administered subcutaneously to pregnant Swiss mice immediately after oral administration of 25 mg/kg methyl mercury chloride (MMC) given on Day 10 of gestation, and at 24, 48, and 72 hr thereafter. DMSA effectiveness was tested at 0, 80, 160, and 320 mg/kg/day. Oral administration of MMC resulted in a high rate of resorptions and dead fetuses as well as a reduced fetal body weight. Moreover, cleft palate (46.9%) and various developmental variations were found in the positive control group. Treatment with DMSA at 160 and 320 mg/kg/day significantly decreased the embryolethality of MMC, whereas at 320 mg DMSA/kg/day the incidence of skeletal anomalies and cleft palate (2.8%) was also significantly reduced. According to these results, DMSA offers encouragement with regard to its therapeutic potential for pregnant women exposed to methyl mercury.