Vascular Endothelial Growth Factor (VEGF) Promotes Proliferation of Trophoblast Cells of In-vitro Parthenogenetic Porcine Embryos.

Abstract

Within the embryonic roadmap the oviduct provides the optimal microenvironment for successful embryo development by its own secretions like fibroblast growth factor, epidermal growth factor, transforming growth factor, vascular endothelial growth factor and others factors that are responsible for successful embryo develop in-vivo. Among the growth promoting factors the VEGF is a multifunctional cytokines that is considered as a potent mitogen for endothelial cells and might be involved in creating an optimal local environment for embryonic development and successful implantation. The present study was conducted to evaluate effects of supplementation of VEGF to the embryo culture medium on the development of porcine in-vitro parthenogenetic embryos by evaluating the cleavage rate, blastocyst formation rate and cell number per embryos. In experiment 1, the parthenogenetic embryos at 1-cell stage were cultured at different concentration of VEGF (0, 5, 50, 500 ng/ml) for 7 days. There was no significant different in the cleavage rate among the treatment groups (70.37±2.91, 74.58±6.15, 75.74±13.64 and 73.66±10.81). However, a significantly (p<0.05) highest number of blastocyst formation was found in the 500 ng/ml group compared to control (66.20±9.93 vs 79.82±9.56). Although, a significantly (p<0.05) highest number of trophoblast was formed in the 500ng/ml group compared to control (44.86±15.85 vs 64.69±27.14) but no significant (p>0.05) different in the ICM formation among the groups. In experiment 2, the parthenogenetic 1-cell stage embryos were cultured in as a control (without VEGF), full term (1-7 days), early (1-3 days) and late (4-7 days) stage in the NCSU 23 medium supplemented with VEGF at 500ng/ml and the cleavage rate and blastocyst formation rate & cell number per blastocyst were evaluated at day 2 and day 7, respectively. A significantly (p<0.05) highest number of trophoblast (73.09±24.16, 77.83±24.54 vs 67.58±22.83, 65.90±20.86) and as well as total cells (84.80±25.81 90.77±25.42 vs 79.56±24.05, 78.26±22.08) were found in the full term and late stage embryo culture system compared to control and early stage culture system, respectively. But, there was no significant difference in ICM formation among these treatment groups. And also there was no significance different in cleavage rate and blastocyst formation among these groups. This result suggests that supplementation of VEGF in the culture medium mainly at late stage that improves the subsequent blastocyst formation specially by increasing the trophoblast cell in the porcine parthenogenetic embryos. This work was supported by a grant (#20070301034040) from BioGreen 21 program, Rural Development Administration Republic of Korea.