Barrier Effect of Placenta Membrane of Pregnant Rat on Mixed Rare Earth Changle

MixedrareearthChangleisamixturecomposedofLa ,Ce ,Pr ,andNdnitrates ,inwhichcontentofCeisthemost .Ithasbeenwidelyusedasafeedad ditiveinanimalhusbandryinChina ,Thefactcuesthatalittlerareearthnitratemaygraduallyenterhu manbodywithconsumptionoffood ,furthermorerareearthnitratecannotbeexcretedcompletelywhilecanbeaccumulatedintheliver ,spleenandbone1] ,theincreasingaccumulationiswithlongertime ,thereforeitisveryimportantthatsafetyofrareearthsnitrateisassessed .Therelationshipbetweenapplieddosean…

Barrier Effect of Placenta Membrane of Pregnant Rat on Mixed Rare Earth Changle

To assess the potential health risks of mixed rare earths Changle for human embryo, whether it crosses placenta membrane or placenta barrier should be determined. In order to arrive at the aim placenta tissue was observed after contamination with optical and electron microscope to show distribution and destiny of mixed rare earth Changle in placenta tissue. Meanwhile the amount of rare earths in serum of pregnant rat, amniotic fluid and extract of embryo tissue were measured by using Inductively Coupled Plasma-Mass Spectrometer (ICP-MS). The rats were administered to 0.3, 2, 5 and 20 mg*kg-1 mixed rare earths Changle every day, respectively by oral from the 6th to 18th day after pregnancy. The results show that many particles are found in syncytiotrophoblast around capillaries of placental villi in contaminated groups under light microscope, and there are more particles following increased dose. It also was observed that some dense bodies with the envelope in placenta membrane and to difference extent damages the mitochondria crista within syncytiotrophoblast cytoplasm in contaminated groups under transmission electron microscope (TEM). Results of ICP-MS assay indicate that the level of Ce increases with contamination dose in the serum of pregnant rats, and the level of total rare earth element remarkably rises in amniotic fluid and serum of pregnant rats for 20 mg*kg-1 group as compared with the control without change for the other groups.