26 PILOT STUDY: YOLK SAC VEGF EXPRESSION IN BOVINE EMBRYOS FROM REPRODUCTIVE TECHNIQUES
A. M. Mess A , A. C. O. Carreira B C , C. Marinovic de Oliveira A , P. Fratini A , P. O. Favaron A , R. S. N. Barreto A , F. V. Meirelles D and M. A. Miglino AA Department of Surgery, Faculty of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, São Paulo, Brazil;
B Chemistry Institute, Biochemistry Department, University of São Paulo, São Paulo, São Paulo, Brazil;
C School of Medicine, NUCEL (Cell and Molecular Therapy Center) and NETCEM (Center for Studies in Cell and Molecular Therapy), Medical Clinics Department, University of São Paulo, São Paulo, São Paulo, Brazil;
D Faculty of Animal Sciences and Food Engineering, University of São Paulo, Pirassununga, São Paulo, Brazil
Reproduction, Fertility and Development 28(2) 143-143 https://doi.org/10.1071/RDv28n2Ab26
Published: 3 December 2015
Abstract
The bovine yolk sac morphology and function are vulnerable to alterations by reproductive techniques. We hypothesised that the early haematopoiesis, vasculogenesis, and angiogenesis of yolk sac affect embryo nutrition and placenta differentiation. A pilot study on bovine yolk sac vascularization was done using gestations with 25, 30, 35, and 40 days of pregnancy, produced by IVF (n = 10) and NT of somatic cell (NT, n = 5). Samples from an abattoir were used as controls (n = 9). All pregnancies were conduced with zebuine cross-breed. We examined yolk sac gross and fine morphology. Also immunohistochemistry and qPCR were done for VEGF-A and receptors (VEGFR-1/Flt-1 and VEGFR-2/KDR). Morphological aspects, including vascularization, of yolk sac from control and IVF groups were tightly similar, although IVF is discretely precocious. However, NT group at Day 30 had low vascularization with thin endothelium, and large intercellular spaces in the endodermal layer, when compared with control and IVF. At Day 35 to 40, NT group improved vascularization and decreased intercellular spaces when compared with early NT samples, remaining less developed than control and IVF. Protein of VEGF-A and receptors (VEGFR-1/Flt-1 and VEGFR-2/KDR) were detected in all groups and ages. The VEGF-A was particularly present in cytoplasm of endodermal, endothelial cells, and in yolk sac blood islands. Furthermore, VEGFR-1 and VEGFR-2 were restricted to endodermal cells. At mRNA level, VEGF-A was highly expressed at Day 25 for IVF (P < 0.05) and at Day 30 for NT (P < 0.05). In addition, VEGFR-1 was highly expressed at Day 30 for IVF group (P < 0.05). For VEGFR-2 high averages were observed at Days 25 and 40 for IVF (P < 0.05). The high expression of VEGF-A and receptors in comparison with control may be due to the precocious yolk sac development in this group. The increase of VEGF-A at Day 30 in NT group is related to the moment of yolk sac vascularization development. In conclusion, yolk sac development is affected by reproductive techniques that alter the vascularization pattern, decreasing embryo nutrition and organogenesis.
