Effects of maternal cadmium exposure during late pregnant period on testicular steroidogenesis in male offspring

Cadmium (Cd) is a testicular toxicant and endocrine disruptor. In the present study, we investigated the effects of maternal Cd exposure during the late pregnant period on testicular development and steroidogenesis in male offspring. Pregnant mice were injected intraperitoneally with CdCl2 (0.5 mg/kg) daily from gestational day (gd) 13 to gd 17. As expected, fetal weight and crown length were significantly decreased in pups whose mothers were exposed to Cd. Importantly, absolute and relative weights of testes were significantly decreased in male fetuses. In addition, maternal Cd exposure during pregnancy markedly reduced serum T level and downregulated the expression of steroidogenic acute regulatory (StAR) protein, P450scc, P45017α and 17β-HSD in testes of male fetuses. Interestingly, the level of serum and testicular T at adulthood remained decreased in male offspring of Cd-exposed mice. Correspondingly, the expression of testicular P450scc was downregulated in male adult offspring whose mothers were exposed to Cd during pregnancy. Fertility analysis found that the number of live fetuses per litter in F2 generation was significantly decreased in Cd-treated group. Additional experiment showed that placental Cd level was increased about 750 folds in dams injected with Cd. However, only traces of blood Cd was measured in fetuses whose mothers were exposed to Cd during the late pregnant period. Taken together, these results suggest that placenta could deter most of Cd from passing from dams to fetuses. The impairments on testicular steroidogenesis in male offspring could not be attributed to a direct action of Cd on fetal testes.

► Maternal cadmium exposure reduces absolute and relative weights of testes.
► Maternal cadmium exposure impairs testicular steroidogenesis in male offspring.
► Impairment on testicular steroidogenesis and testicular P450scc expression was irreversible.
► Placental Cd level was increased about 750 folds. Only traces of blood Cd was measured in fetuses.