MIYAIRI Shinichi Nihon University, Pharmacology, Professor (50209855)
OSUGA Yutaka University of Tokyo, Medicine, Assistant Professor (80260496)
USUI Mayumi Saitama Medical University, Medicine, Assistant Professor (60383270)
岩田 睦 埼玉医科大学, 医学部, 助手 (20364804)
|Budget Amount *help
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2006: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2005: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2004: ¥1,400,000 (Direct Cost: ¥1,400,000)
1. Maternal and fetal exposure to dioxins
The concentrations of dioxins (PCDDs, PCDFs and Co-PCBs) were determined in maternal and umbilical cord blood and amniotic fluid. There was a significant positive correlation between maternal age and maternal blood Co-PCBs, and also a significant positive correlation in total dioxin, PCDDs and Co-PCBs concentration between the maternal and umbilical cord blood, suggesting transplacental dioxin translocation. It was also shown that PCDDs and PCDFs are likely to accumulate in the lipid components in the amniotic fluid. Moreover, it was suggested that fetal dioxin exposure may affect fetal and neonatal thyroid function.
2. Effects of prenatal exposure to indirubin on offspring
Indirubin, which was found in human urine, has 50-times higher affinity to dioxin receptor (Ah receptor) and its biological function remains to be elucidated. Pregnant mice were administered on 14.5 dpc with 1) indirubin, 2) 7,8-benzoflavone (Ah receptor inhibitor), 3) indirubi
n + 7,8-benzoflavone, and 4) DMSO alone. Birth weight of pups in groups 1) and 2) were significantly lower in those in 3) and 4), and follicle numbers in the ovaries on postnatal day 4 was lower in indirubin-treated groups.
3. Indirubin concentration in maternal urine and amniotic fluid
Indirubin concentration in the maternal blood in first (12-15 weeks), second (21-24 weeks), and third (33-36 weeks) trimester of their gestational period was determined by indirubin-specific ELJSA. Indirubin level in third trimester was significantly higher than those in first trimester. Birth weight, however, was not significantly correlated with the maternal indirubin level. Indirubin level was below the detectable limits in the amniotic fluid obtained in second and third trimester.
These results suggest that fetal exposure to indirubin may affect neonatal development and reproductive function, and that pregnant women are likely to be exposed to higher level of indirubin than non-pregnant women. However, it is also suggested that indirubin exposure of human fetus may remain insignificant. Less