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Accumulation and influence of mercury released from dental amalgam in living body

牙科汞合金释放汞在生物体内的富集及其影响

基本信息

批准号：
04671200
负责人：
TAKAHASHI Yoshifumi
金额：
$ 1.34万
依托单位：
Aichi-Gakuin University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1993
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-04671200/
关键词：
Amalgam Mercury Pregnant rat Fetus Brain Liver Kidney Blood 臓器中水銀濃度

项目摘要

This study was carried out to obtain information regarding the accumulation and influence of mercury released from dental amalgam in a livin body. To address this object we have employed an experimental animal model in which pregant rat received amalgam tooth fillings. We measured a total mercury in organs and blood samples of mother and their fetus. The results obatined in this study were summarized as follows.Experiment 1.Mercury from dental amalgam appeared in maternal and fetal organs after amalgam tooth restorations in the mother rtas. In mothers, the mercury concentrations of the brains, livers, kidneys and placentas from the experimental group were significantly higher than those of the controls, and the highest mercury was found in the kidneys, followed by placenta, liver and brain. In fetuses, the mercury concentrations of the brain, liver from the experimental group were significantly higher than those of the controls. The highest mercury concentration among fetal organs was … More found in liver, followed by kidneys and brain.Experiment 2.With the increasing number of amalgam fillings, mercury concentrations in organs of mother and their fetuses tended to increase, while body weight of fetus tended to decrease.Experiment 3.In order to examine the influence of amalgam fillings on growth of fetuses, 4 teeth were fillied with the glass ionomer cement instead of amalgam. In mothers, growth curves of the experimental animals was lower than that of the control animals. Intake of the diet and water were significantly lower than those of the controls at the early pregnant stage. Althogh, significant difference was not observed, body weight of the fetus was lower than that of the controls. These results indicated that dental treatment itself seemed to influence the intake of the diet and water at the early pregnant stage and to slow the growth of mother rats and their fetuses. These findings of this study and the results of the experiment 2 suggested that it was likely that amalgam fillings themselves did not influence the growth of fetuses.Experiment 4.This study was carried out to examine the relation between amalgam fillings in pregnant rats and marcury concentrations in organs of offspring's of second and third generations. The mercury contents in the brain, liver, kidney and spleen of the experimental animals of the second generation were higher than those of the controls, although significant differences were not observed. In the third generation, mercury concentrations were almost the same between experimental and control groups.Experiment 5.This expriment was carried out to examine the chemical form of mercury accumulated in organs of mother rats and their fetuses. In mothers, the mercury contents in the whole blood, erythrocyte and plasma of the experimental animals were significantly higher than those of the controls. In fetuses, the mercury contents in the whole blood of the experimental animals were significantly higher than that of the controls. Fetus to mother ratio, and Erythrocyte and plasma ratio of the experimental animals were lower than those of the controls. On the other hand, PF ratio of the experimental group was higher than that of the control group. Chemical transformation of elemental mercury after introduction into fetuses remains unclear, though it is suggested that elemental mercury undergoes an oxidation process similar to that occurring in maternal animals. Ratios of mercury concentrations in erythrocytes and plasma depend upon the chemical forms of mercury compounds ; after mercury exposure to mercury vapor, more mercury is found in red cells than in the plasma, but after inorganic mercury exposure, the reverse is true. In this experiment, the erythrocyte to plasma ratio of mothers of the experimental group was significantly lower than that of the control group. This indicates that the chemical form existing in the blood stream is possibly inorganic. In the fetal organs, blood returning from the placenta through the umbilical veins enters fetal circulation through the ductus venosus, mainly by passing through the liver. Furthermore, it is known that catalase has a great capacity to oxidized mercury vapor into ionic mercury and that this enzyme is contained abundantly in liver. The chemical form of mercury passing through the placental barrier is possibly elemental. Although we could not examined the mercury concentration ratio of erythrocytes and plasma in the blood sample of the fetus, mercury in the fetal circulation system is possibly inorganic because the highest mercury accumulation was found in the liver. Consequently, it is most likely that part of the mercury released from the dental amalgam filling passing the placenta is oxidized into ionic mercury in fetal liver and accumulates in that organ. Less

本研究旨在获得有关牙科汞合金释放的汞在活体中的累积和影响的信息。为了解决这个问题，我们采用了一种实验动物模型，其中怀孕大鼠接受汞合金牙齿填充物。我们测定了母亲及其胎儿的器官和血液样品中的总汞。本研究得到的结果总结如下：实验1.在母亲区域性牙种植体中进行银汞合金牙齿修复后，来自牙科银汞合金的汞出现在母亲和胎儿的器官中。在母亲中，实验组的大脑，肝脏，肾脏和胎盘中的汞浓度显著高于对照组，肾脏中的汞含量最高，其次是胎盘，肝脏和大脑。胎鼠脑、肝汞含量实验组明显高于对照组。胎儿器官中汞浓度最高的是 ...更多信息实验2.随着汞合金充填次数的增加，母体及胎儿各器官中汞含量呈增加趋势，胎儿体重呈下降趋势。在母体中，实验动物的生长曲线低于对照动物。在妊娠早期，试验组的饲料和水摄入量均显著低于对照组。但胎仔体重低于对照组，差异无显著性。这些结果表明，牙科治疗本身似乎影响了妊娠早期的饮食和水的摄入，并减缓了母鼠及其胎儿的生长。本研究的结果和实验2的结果表明，汞合金填充物本身可能并不影响胎儿的生长。实验4.本研究旨在研究妊娠大鼠汞合金填充物与第二代和第三代子代器官中汞的浓度之间的关系。第二代实验动物脑、肝、肾、脾中汞含量均高于对照组，但差异不显著。第三代实验组与对照组汞含量基本相同。实验5.本实验研究了汞在母鼠和胎鼠体内蓄积的化学形态。母体全血、红细胞和血浆中汞含量均显著高于对照组。在胎儿期，实验动物全血中汞含量显著高于对照组。胎母比、红细胞/血浆比均低于对照组。另一方面，实验组的PF比率高于对照组。元素汞进入胎儿体内后的化学转化尚不清楚，但有人认为，元素汞会经历一个类似于母体动物体内发生的氧化过程。红细胞和血浆中汞浓度的比率取决于汞化合物的化学形式;汞暴露于汞蒸气后，红细胞中的汞多于血浆中的汞，但无机汞暴露后，情况正好相反。在本实验中，实验组母亲的红细胞/血浆比值显著低于对照组。这表明存在于血流中的化学形式可能是无机的。在胎儿器官中，从胎盘通过脐静脉返回的血液通过静脉导管进入胎儿循环，主要是通过肝脏。此外，已知过氧化氢酶具有将汞蒸气氧化成离子汞的巨大能力，并且这种酶在肝脏中含量丰富。通过胎盘屏障的汞的化学形式可能是元素。虽然我们无法检测到胎儿血液样本中红细胞和血浆中汞的浓度比，但胎儿循环系统中的汞可能是无机的，因为发现肝脏中汞积累最高。因此，很可能是牙齿汞合金填充物通过胎盘释放的部分汞在胎儿肝脏中被氧化成离子汞，并在该器官中积累。少