Regulation of manganese accumulation in perinatally exposed rat pups

The risk of manganese (Mn)-related ill effects in the neonate has been the topic of several investigations because in formula-fed infants Mn intake is much higher than in breast-fed infants. In the young, when Mn homeostasis is not yet developed, increased Mn intake might pose a neurotoxic risk. Our work aimed at collecting new data on Mn accumulation during the perinatal period by using an experimental rat model in pups whose mothers were exposed orally to Mn in drink (as manganese chloride; dose of 2000 ppm Mn) throughout pregnancy and 11 days of lactation. Pups were cross-fostered at birth and placental and mammary transfer of Mn at birth and at the age of 11 days was evaluated. The total pup body burden of Mn was analysed by atomic absorption spectrometry. Concentrations of iron (Fe), zinc (Zn) and calcium (Ca) also were analysed at the end of the experiment. The concentration of Mn in perinatally exposed pups was 6-8 times higher than in controls, irrespective of the period and duration of exposure. After cessation of exposure, the Mn concentration decreased almost to control levels. Concentrations of other essential elements (Fe, Zn, Ca) were not affected by Mn exposure. Our results indicate the existence of an accurate regulation of Mn accumulation in pups exposed to Mn during the perinatal period.