[Morphological research on brain development and expression of vital cytokines in brain of human 6-8 week old embryo aborted for unexpected cause].

OBJECTIVE: To clarify the changes in cell proliferation, differentiation, apoptosis and in the expression of vital cytokines during development of 6-8 week old embryo, and hence provide the evidence for identifying the mechanisms of cell proliferation, differentiation, apoptosis during early developing human embryonic brain. METHODS: Human aborted embryos were obtained with the consents signed by the pregnant women with unexpected abortions in gestation of 6-8 weeks. The histochemical SABC method and TUNEL Staining were employed to this research project. RESULTS: At 6 weeks, two telencephalons, diencephalon, mesencephalon, metencephalon, and myelencephalon have been formed, and from week 6 to 8, every cerebral vesicle has had three layer cells including germinal layer (GL), intermediate layer ( IL ), and marginal zone (MZ). At 6-7 weeks, TUNEL-labeled cells and PCNA-, Bcl-2-, Bax-, Fas-, Fas-L-, Rb- and P53-positive cells were all observed in the GL and IL of the five brain regions, positive deposition appeared in nuclei. At week 8, Fas- and Rb-positive cells were observed in the IL of the five brain regions, positive deposition appeared in cytoplasm and cell processes, and no changes in the distributions of TUNEL-labeled cells and positive cells regarding the other five factors. The expressions of the cytokines were in agreement with the occurrence of the neuronal proliferation and apoptosis temporally and in space. CONCLUSION: During development in early embryo brain, neural precursor cell proliferation and apoptosis occur simultaneously. Fas, FasL and Bax may be involved in the induction of cell apoptosis. Bcl-2 probably prevents the cell apoptosis and provides a survival signal for cells. Rb and P53 may play a critical role in monitoring and maintaining the normal neural precursor cell to proliferation and differentiation.

[Expression of CD34, CD14, CD10, CD31 and factor VIII on hematopoietic cells of yolk sac blood island, AGM region and liver of human embryo and fetus].

OBJECTIVES: To study the expression of CD34, CD31, CD14, CD10 and factor VIII on blood island of yolk sac (YS), PAS/aorta-germen-mesonephros (AGM) region and hepatic hematopoietic foci. METHODS: Thirty-two cases of 3rd-12th weeks human embryo were obtained by drug abortion. Paraffin embedded sections with H.E staining and immunohistochemistry reaction (SABC) were performed. RESULTS: YS blood island of 3rd-4th weeks of gestation was consisted of two types of cells. One was vascular endothelial cells located outside and the other hematopoietic cells inside the blood island. Both the two types of cells were CD10, CD14, CD31 and factor VIII positive. Hematopoietic cells were CD34 negative, and vascular endothelial cells were CD34 positive. On 32nd days of gestation, the hematopoietic cells migrated out of YS. On 4th week of gestation, CD34, CD14, CD10, CD31 and factor VIII positive cells appeared in the aorta, mesonephros and hepatic hematopoietic foci. By the 7th week, the number of positive hematopoietic cells reached the peak. In 11th-12th weeks, most cells in these regions were matured red blood cells and were negative for all the antibodies mentioned above excepting for CD34. During 4th-12th weeks, all endothelial cells in embryo were CD34 positive. CONCLUSIONS: The hematopoietic cells and endothelial cells of YS blood island co-expressed CD10, CD14, CD31 and factor VIII. Endothelial cells were CD34 positive but hematopoietic cells were negative in YS blood island. The hematopoietic cells of aorta, mesonephros and hepatic hematopoietic foci expressed CD34, CD10, CD14 and factor VIII from 4th week to 7th week. Anti-CD34 antibody could label endothelial cells of every kinds vessels of embryo from 3rd to 12th weeks.

[Expression of HNF4alpha and HNF6 mRNA during the process of mouse liver development].

OBJECTIVE: To investigate the function of HNF4a and HNF6 during liver development. METHODS: The expression levels of HNF4alpha and HNF6 at E8, 9, 13, 15, 17, P1 and in adult mouse liver were detected by RT-PCR and in situ hybridization. RESULTS: RT-PCR results showed that HNF4alpha first expressed at E9, the time of liver bud formation, and lasted through all gestation and existed in adult liver. In situ hybridization showed that the expression of HNF4alpha was detected at the cells of liver cords during various stages of mouse liver development, and there were still a few HNF4alpha positive hepatocytes in adult liver. The cells of bile duct plate and biliary epithelial cells, endothelial cells, hematopoietic cells of liver were negative for HNF4alpha. The expression of HNF6 mRNA was detected in the liver at E9, the time of liver formation onset. Then, HNF6 mRNA disappeared transiently at E13, but it appeared again at E15. Its expression lasted until adult. In situ hybridization studies showed that most liver cord cells were positive for HNF6 at E9 and E15. At E17 and P1, the expression levels of liver cord cells declined, and HNF6 strongly expressed in the cells of bile duct plate and biliary epithelial cells. CONCLUSION: HNF4alpha could modulate the formation of liver bud, trigger the differentiation of hepatic stem cell towards hepatocytes, and keep the shape of hepatocytes. HNF6 might play a role at the onset of liver development, in the differentiation of hepatic stem cell towards biliary epithelial cells, and in maintaining the morphological characteristic of biliary epithelial cells.

[Expression of VEGFA, VEGFC, angiopoietin-1, angiopoietin-2 and their receptors on development liver during gestation of weeks 3-12 of human embryo].

The aim was to study the expression of VEGF-A, VEGF-C, angiopoietin-1, angiopoietin-2 and their receptors on development liver during gestation of weeks 3-12 of human embryo. Human embryo contingently aborted at 3-12 weeks of gestation were collected with signed agreements of the pregnant women suffered from accidental abortions. The specimens were fixed by 4% paraformaldehyde and embedded by paraffin. 5 microm serial sections were made. HE staining, immunohistochemistry method and light-microscope were employed. The results showed that at 4-5 weeks of development, liver was constituted by a few hepatic cords. Hematopoietic cell or blood cells were undetectable in the 4 week of gestation. A few cells which were larger, rounded and nucleared cells appeared and expressed VEGFA, flt-4 and Tie-2 proteins strongly in liver at 5 weeks of gestation. The number of these immuno-positive cells was highest in the 7th week and decreased at 11-12 weeks of gestation. These cells expressed flk-1 transiently in the 6th week. VEGF-C and flt-1 were expressed by hepatic cells from weeks 7 to 12 of gestation. The immuno-positive products were deposited in plasma of hepatic cells. Angiopoietin-1, angiopoietin-2 and Tie-2 were detectable on those cells which expressed VEGFA, flt-4 and Tie-2 from weeks 5 to 12 of gestation. The expression of angiopoietin-1 and angiopoietin-2 were weakly and Tie-2 was strongly. They were expressed weakly too by hepatic cells at 5 to 12 weeks of gestation. All factors and their receptors were undetectable on vascular endothelial cells at 4-12 weeks of gestation. It is concluded that the expression patterns of VEGF family on cells of liver are different before and after 7 weeks of gestation. The hematopoiesis in fetal liver may be related to development of hepatic cell.

[Expression of VEGFA, VEGFC, angiopoietin-1, angiopoietin-2 and their receptors on yolk sac blood island, aorta-gonad-mesonephros (AGM) region of human embryo].

The study was to investigate the expression of VEGFA, VEGFC, angiopoietin-1, angiopoietin-2 and their receptors on yolk sac blood island, AGM region during gestation of 3th-12th weeks of human embryo. Human embryo contingently aborted at 3 - 12 weeks of gestation were collected with signed agreements of the pregnant women suffered from accidental abortions. The specimens were fixed by 4% paraformaldehyde and embedded by paraffin. 5 micro m serial sections were made. HE and immunohistochemistry method (SABC) and light-microscope were employed. The results showed that VEGFA and its receptors flt1/flk-1, VEGFC and its receptor flt-4, angiopoietin-2 and its receptor tie-2 proteins were expressed strongly and angiopoietin-1 was weakly expressed by hematopoietic cells and vascular endothelial cells of blood island at 21 and 25 days of gestation. In the 4th week of gestation, immuno-positive reaction of these factors and their receptors appeared in the aorta and mesonephros deposited in larger, rounded and nucleated cells which represented hematopoietic cells. Up to 7th week, positive hematopoietic cells in the regions were much abundant. The number of positive cells decreased at 8th week. Up to 12th week, almost all blood cells were immuno-negative. VEGFA, flt-1, flt-4, angiopoietin-1, angiopoietin-2 and Tie-2 protein were expressed mainly by gonad at 6 - 8 weeks, but it did not express VEGFC and flk-1. The immuno-reaction of the factors and their receptors could not detected in vascular endothelial cells during 3-12th weeks of gestation. It is concluded that hematopoietic cells and endothelial cells in blood island of yolk sac, mesonephros and dorsal aorta co-expressed some factors and their receptors in relation to vasculogenesis and hematopoiesis. Intraembryonic hematopoiesis began in the 4th week of gestation.