Effects of methylmercury and mercuric chloride on preimplantation mouse embryos in vivo

Abstract

This report compares the effects of methylmercuric chloride (MMC) and mercuric chloride (MC) on the development of mouse preimplantation embryos in vivo. Female mice were injected with a single intravenous dose of 0.5-20.0 mg Hg/kg MMC or 0.5-2.5 mg Hg/kg MC on day 0 of gestation. The embryos were recovered by flushing excised oviduct and uterus on day 3.5 of pregnancy, and were examined for abnormalities. In the groups treated with doses of 0.5 and 1.0 mg Hg/kg of both compounds, the rates of abnormal embryos were not significantly different from that in the control group. The 50% effective dose of MMC was twice as great as that of MC. With increasing dose, the difference became more obvious; the 80% effective doses differed by a factor of ten. The body weight of dams decreased in terms of the dose of mercury in MC-treated groups, but did not vary in MMC-treated groups. The sensitive developmental stage for mercury toxicities could not be determined clearly, although the high sensitivity was reported in the blastocyst stage in vitro. The embryos treated in vivo were less sensitive than those reported in vitro.

Mechanisms involved in the transport of mercuric ions in target tissues

“…The deleterious effects of CH 3 Hg + on fetal development have been recognized widely as one of the most serious toxicological consequences of CH 3 Hg + exposure (Amin-Zaki et al 1974; Davidson et al 2008; Harada 1978, 1995; Inouye and Kajiwara 1988; Kajiwara and Inouye 1986, 1992; Matsumoto et al 1965). Following maternal exposure to CH 3 Hg + , mercuric ions are taken up readily by the placenta and accumulate subsequently in both placental and fetal tissues (Ask et al 2002; Inouye and Kajiwara 1988; Inouye et al 1985).…”

Metals and female reproductive toxicity

“…However, embryos exposed in vivo were less sensitive to damage than those exposed in vitro. 111…”

Transport of Inorganic Mercury and Methylmercury in Target Tissues and Organs

“…The deleterious effects of CH 3 Hg + on fetal development have been recognized widely as one of the most serious toxicological consequences of CH 3 Hg + exposure (Matsumoto et al, 1965; Amin-Zaki et al, 1974; Harada, 1978; 1995; Kajiwara & Inouye, 1986; Inouye & Kajiwara, 1988; Kajiwara & Inouye, 1992; Davidson et al, 2008). Following maternal exposure to CH 3 Hg + , mercuric ions are taken up readily by the placenta and accumulate subsequently in both placental and fetal tissues (Inouye et al, 1985; Inouye & Kajiwara, 1988; Ask et al, 2002).…”