Effect of gestational cadmium exposure on fetal growth, polyubiquitinated protein and monoubiqutin levels in the fetal liver of mice.

Cadmium (Cd) is an environmental pollutant present in contaminated water, food and soil. Cd adversely affects fetal development. We exposed pregnant mice to daily oral doses of 5 and 10 mg/kg Cd and examined fetal growth. It was demonstrated that the exposure to Cd (10 mg/kg) during gestation caused fetal growth retardation (FGR). Investigation of the ubiquitin-proteasome system in fetal livers of mice exposed to gestational Cd revealed increased polyubiquitinated protein accumulation, contrasting with decreased levels of monoubiquitin protein. Moreover, the expression level of Ubc (encoding polyubiquitin C protein) was significantly decreased in 5 and 10 mg/kg Cd-treated groups in comparison with the control group. Therefore, we propose that decrease of monoubiquitin level and accumulation of polyubiquitinated protein in the fetal liver may be important factors in Cd-induced FGR.