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Domestic animal endocrinology

Vascular endothelial growth factor A improves quality of matured porcine oocytes and developing parthenotes.


PMID 25061966

Abstract

Vascular endothelial growth factor is a multipotent angiogenic factor implicated in cell survival and proliferation. The objective was to determine effects of exogenous recombinant human VEGFA (or VEGFA165) in culture media on porcine oocyte maturation and parthenote development. Adding 5xa0ng/mL VEGFA to the culture medium improved the maturation rate of denuded oocytes (P < 0.05), although 5, 50, or 500xa0ng/mL did not significantly affect nuclear maturation of oocytes. Parthenotes from oocytes cultured either in inxa0vitro maturation or inxa0vitro culture medium supplemented with 5 or 50xa0ng/mL VEGFA had an improved blastocyst rate and increased total numbers of cells (P < 0.05). Moreover, those treated with 5xa0ng/mL of VEGFA had a higher hatched blastocyst rate (average of 121 cells per blastocyst). All VEGFA-treated oocytes had reduced apoptotic indices (P < 0.05), except for those with a higher dose (500xa0ng/mL) of VEGFA which had more apoptotic cells (P < 0.05). Adding 5xa0ng/mL VEGFA to oocytes during the last 22xa0h of inxa0vitro maturation improved (P < 0.05) blastocyst rates and total numbers of cells, with reduced apoptosis indices similar to that of long-term (44xa0h) culture. Furthermore, Axitinib (VEGFR inhibitor) reversed the effects of VEGFA on parthenote development (P < 0.05). Follicular fluids from medium (2-6xa0mm) to large (>6xa0mm) follicles contained 5.3 and 7.0xa0ng/mL vascular endothelial growth factor protein, respectively, higher (P < 0.05) than concentrations in small (<2xa0mm) follicles (0.4xa0ng/mL). Also, VEGFA and its receptor (VEGFR-2) were detected (immunohistochemistry) in growing follicles and developing blastocysts. In addition, VEGFA inhibited caspase-3 activation in matured oocytes (P < 0.05). In conclusion, this is apparently the first report that VEGFA has proliferative and cytoprotective roles in maturing porcine oocytes and parthenotes. Furthermore, an optimal VEGFA concentration promoted porcine oocyte maturation and subsequent development.