Determination of Manganese in Bone Among Treated Neonate Rats

Manganese (Mn) is an essential nutrient to humans; however, elevated levels have been associated with neurological deficits such as attention deficit hyperactivity disorder.  Exposure to elevated levels of Mn in neonates and young children can impact neurodevelopment while occupationally exposed adults develop manganism, a disease similar to Parkinson’s disease.  Previous studies have shown that there is an increase in blood Mn levels over the first through third trimester of pregnancy to levels comparable to occupationally exposed workers.  It is hypothesized that increased bone mobilization contributes to these elevated levels in pregnancy.  Previous studies on lead (Pb) have shown that bone turnover during pregnancy/lactation introduces Pb from bone back into circulation; this may perhaps be the case for Mn.  In order to test this hypothesis rats were treated using three oral Mn dose levels and two durations of exposures from post natal day (PND) 1-21 and PND 1-lifelong.  The femur was dissected and analyzed using inductively coupled plasma mass spectrometry to determine if Mn accumulation occurs in bone – a first step to address the hypothesis. Extended X-ray absorption fine structure analysis will be used on the tibia and fibula to determine molecular coordination and valence state of Mn.  It is expected that Mn will accumulate in bone in both the low and high Mn-treated animals.   It is also expected that Mn incorporation will not affect calcium levels. The data obtained will better link the relationship between Mn exposure, bone Mn accumulation, and remobilization during pregnancy and fetal development.