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| Author(s): |
Claudia Marinovic de Oliveira
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Medicina Veterinária e Zootecnia (FMVZ/SBD) |
| Defense date: | 2011-12-19 |
| Examining board members: |
Maria Angélica Miglino;
Ana Flávia de Carvalho;
Moacir Franco de Oliveira;
Felipe Perecin;
Rose Elí Grassi Rici
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| Advisor: | Maria Angélica Miglino |
| Abstract | |
High mortality rates occur during embryonic implantation embryos from IVF and FTAI. It is believed that the failure in the development of the yolk sac may be related to these embryonic losses. The objective of this study was to describe the macroscopic, microscopic and mRNA expression features of the yolk sac involution process, since the literature relates contradictory information regarding the processes of formation and involution of the yolk sac in IVF and TAI embryos. Nineteen embryos were used for FTAI and 16 IVF; the specimes were obtained from the Sociedade Agropecuária Imaculada Conceição-Redenção/PA, Brazil. No significant differences were observed in the size of embryos aged 25 (p = 0.1), 35 (p = 0.1), 40 (p = 0.4) and 45 (p = 0.36) days in the groups of IVF and FTAI. However between FTAI and IVF embryos with 30 days of gestation, a difference (p = 0.03) was detectable. The growth curve (Crow-Rump) increased gradually and linearly with gestational age. Macroscopically, it was observed that after 25 days of gestation, the yolk sac was \"T-shaped\" and transparent colored. A central portion was observed in the vicinity of the ventral ends of the embryo exhibiting two thin membranes, which accompanied the allantois with the umbilical vessels. At 30 to 35 days this portion becomes yellowish and its central part together with the extremities was reduced displaying clearly signs of regression. At 40 to 45 days, the process of involution was presented in a curled fashion and ends with the central region resembling a flat small grain in contact with the amnion. Microscopically, the yolk sac was formed by three layers: the endoderm, single layer lining the vitelline cavity, an intermediate layer and vascular mesenchymal mesothelium, exoceloma focused on single layer. The epithelium of the yolk sac formed folds or crypts, which projected to the light. Immunohistochemistry marking was noted for antibodies VEGF, Flt-1 and KDR. No significant difference were observed in mRNA expression of VEGF, KDR and Flt-1 between groups and the gestational ages analyzed at 30 days there has been a trend among the groups regarding the expression of Flt-1. The growth factors bFGF, FGFR-1 and FGFR-2 showed no differences in their expressions, with the exception of 35 days of gestation for the m-RNA FGFR 1. It was concluded that the yolk sac is strongly related to embryonic development, in which the involution and disappearance are related to growth and \"maturity\" stage. (AU) | |