Study On Angiogenesis And Relative Regulated-factor In The Villi Of Human Placenta

PurposeExpression of vascular endothelial growth factor(VEGF), basic fibroblast growth factor(bFGF) and transforming growth factor betal(TGF 3 1) in human placenta trophoblast and variety of vascular density in placental villi during pregnancy were studied.MethodsPlacental samples obtained from 30 women were divided into 3 groups . ei the first trimester group, the second trimester group and the term group. Each group contained 10 placental samples. The gestational duration was 6-9weeks, 18-22 weeks and 37-38 weeks respectively. A induced abortion was performed in the first trimester group, and a labor induced via extra-amniotic insertion of water bag was performed in the second trimester group and a caeserioa section was performed in the term group. All samples fixed in formalin solution for were morphological study stained and trophoblastic layer was analysed HE and immunohistochemistry for light microscopic observation and immunohistochemical analysis.Result1.Morphology of placental villi:A. The first trimester group: the numbers of placental villi were little in number but their volumes became wider, the boundary between syncytiotrophoblast and cytotrophoblast was distinct. Microvessels located in the center of placental villi could be seen. Endothelial cells were thickened. B. the second trimester group: the number of placental villi increased markedly. Comparing with the first trimester group, their volumes decreased and the cytotrophoblast was indistinct. The endothelial cells of microvessels were flatened in shape. C. the term group : The trophoblastic layer was not evenly thickened. The number of microvessels increased obviously, but the vessel volumes were not obviously dilated.2.Stereology of placental villous vessels :In the course of pregnancy, radial parameters of vessels was insignificantly changed (26.67±7.14, 25.08±4.67,23.36±5.30, P>0.05 respectively) and the length density of vessels was statistically and significantly increased (1.46±0.64, 5.58±1.31, 19.56±1.40, P<0.01 respectively).3.Expression of VEGF, bFGF and TGF- β1 in human placenta trophoblast :In the course of pregnancy, the stain intensity of each growth factor in trophoblast decreased significantly (VEGF: 28.19 ± 3.01, 18.65± 2.43, 4.95± 0.86, P<0. 01; bFGF: 16.80±1.23, 9.92±1.65, 4.18±0.52, P<0.01; TGF-β 1: 15.54±2.56, 7.58±1.77, 3.24±0.87, P<0.01 respectively).Conclusion1.Hypoxic environment and placental cell apotosis might regulate morphologicalchanges of trophoblast.2. In the course of pregnancy, the increasing number of microvessels in placental villiis important to fetal growth and maternal-fetal material exchange, but the vesselvolume was insignificantly changed .3.Angiogenesis in chorioncal villi is a complex process. The decrease of VEGF, bFGFand TGF- β 1 expression in the course of pregnancy indicates that other factors mighttake part in the regulation of angiogenesis.