The Dynamic Distribution Of ⁶³Ni In The Rats And Fetuses In Latter Pregnancy

Background:In our preliminary study,the rats have a pregnancy after three weeks when pure metal nickel were implanted into the right hind limb of rats,the results showed that nickel could accumulate in the maternal kidney in latter pregnancy,concentration of nickel in blood increased.Nickel in maternal blood passed through the rat placenta to distribute and accumulate in the fetus and the amniotic fluid.But it's not clear about nickel that how to distribute in the maternal and fetal organs in latter pregnancy.Objective:After a single intraperitoneal injection of ⁶³NiCl₂ into a rat on the 20th day of gestation,the change of concentration of ⁶³Ni in the maternal and fetal organs at different time and distribution in the fetuses were detected by liquid scintillation counting spectrometry and autoradiography in order to study the dynamic distribution in the organs and how to effect the embryo development.Methods:35 rats on the 20th day of gestation were randomly divided into 7 groups according to the sacrifice time,A single injection of ⁶³NiCl₂(640 kBq/kg) was administered to a rat by intraperitoneal injection.The pregnant rats were deep anesthesia at intervals of 0.5,1,3,6,9,12 and 24 h after injection,firstly,the whole blood was withdrawn from femoral artery,samples of the maternal organs and fetuses or the fetal organs were collected.After normal saline washing,drying,weighing,the organs were frozen under -80℃.The amniotic water and fetal blood were collected. The dynamic distribution of ⁶³Ni in pregnant rats and their fetuses was studied by liquid scintillation counting spectrometry and autoradiography.Results: 1.Concentration of ⁶³Ni:(1) Maternal rats:concentration of ⁶³Ni in blood reached the peak at 0.5 h after injection.Those of kidney,brain,liver,heart,lung and stomach reached the maximum levels at 3 h after injection.The relative concentration of ⁶³Ni in the maternal organs changed as follows(from the order of highest to lowest concentrations):3 h:kidney＞lung＞heart＞stomach＞liver＞brain;9 h:kidney＞lung＞stomach＞liver＞heart＞brain; 24 h:kidney＞lung＞stomach＞liver＞heart＞brain.(2) Fetus:concentration of ⁶³Ni in the blood and heart reached the peak at 3 h after injection,but those of brain,kidney, stomach,liver and rib cartilage at 9 h.Concentration of ⁶³Ni in lung continued to increase within 24 h after injection.The concentration of ⁶³Ni in the maternal organs changed as follows(from the order of highest to lowest concentrations):3 h:heart＞kidney＞bone＞liver＞lung＞stomach＞brain;9 h:kidney＞bone＞stomach＞liver＞heart＞brain＞lung;24 h:kidney＞lung＞bone＞liver＞stomach＞heart＞brain.(3) Placenta,fetus and amniotic fluid:concentration of ⁶³Ni in placenta reached the peak at 3 h but 9 h for fetus after injection and then decreased;concentration of ⁶³Ni in the amniotic fluid increased slowly at 9 h after injection,but after 9 h rapid increased.(4) The concentrations of ⁶³Ni in maternal organs compared with those of fetal organs: The concentration of ⁶³Ni in fetal heart was higher than that of the maternal heart 1 h after injection;the concentration of ⁶³Ni in fetal brain,liver and stomach was higher than that of the maternal 6 h after injection;the concentration of ⁶³Ni in fetal lung was higher than that of the maternal 12 h after injection.2.Radioactive distribution of ⁶³Ni in the fetus:autoradiography showed that ⁶³Ni distributed in the fetal cartilage,liver,kidney,heart and stomach.Conclusions:(1) Higher concentrations of ⁶³Ni in maternal kidney and lung may be associated with Ni-binding protein content in them.Lower concentrations of ⁶³Ni in brain suggested that ⁶³Ni is not prompted to cross the blood-brain barrier and enter maternal brain within 24 h.(2) The time when ⁶³Ni concentrations of fetal brain,liver and stomach attach to peak is delayed 6 h,which may be related to the delayed effect of the placental barrier.(3) Concentrations of ⁶³Ni in fetal organs at 6 h after injection are higher than those of maternal organs,it may be that ⁶³Ni can be discharged from mother but can not be from fetus effectively.