VEGFA、VEGFC及其受体和angiopoietin-1/angiopoietin-2及其受体在发育第3-12周人胚胎肝的表达

本研究观察VEGFA和VEGFC及其受体和angiopoietin-1／angiopoietin-2及其受体在发育第3—12周人胚胎肝的表达。在征得意外流产孕妇同意并签字后，收集其意外流产受精龄为第3—12周的人胚胎，4％多聚甲醛固定，石蜡包埋切片，HE和免疫组织化学染色，光镜观察。结果表明：在发育第4周，肝由少量肝索组成，肝内未见造血细胞和血细胞。肝内大、圆、有核的原始血细胞于发育第5周开始出现，并强表达VEGFA、flt-4和Tie-2，其数量在发育第7周达高峰。第11—12周，阳性细胞数量减少。这类细胞仅于发育第6周时短暂表达Flk-1。第7—12周，肝细胞表达VEGFC和flt-1，阳性反应产物积聚在细胞质中。发育第5周到第12周胚胎肝血管内，有angiopoie—tin-1和angiopoietin-2阳性反应的细胞存在，细胞形态同上述VEGFA、fkt-4和Tie-2阳性细胞。angiopoietin-1和angiopoietin-2阳性反应较弱，Tie-2的免疫反应强。发育各期，肝细胞也弱表达angiopoietin-1和angiopoiefin-2和Tie-2。发育各期血管内皮细胞为上述各种因子和受体阴性反应。结论：发育第7周之前和第7周之后，VEGF家族及其受体在肝内造血灶的细胞表达模式不同。胎肝造血与肝细胞的发育可能相关。

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.