Influence of vascular endothelial growth factor and Cysteamine on in vitro bovine oocyte maturation and subsequent embryo development

Abstract

The objective of this study was to investigate the effect of VEGF and Cysteamine during in vitro maturation (IVM) of bovine oocytes on GSH content and developmental competence. For this purpose, experiments were designed to evaluate the effect of 0, 100, 300, and 500ng/mL VEGF in IVM medium on: GSH content in oocytes and cumulus cells (Exp. 1) and subsequent embryo development (Exp. 2). Also, influence of adding 500ng/mL VEGF and 100μM Cysteamine to IVM medium on GSH content in oocytes and cumulus cells (Exp. 3) and oocyte developmental capacity (Exp. 4) were evaluated. Oocytes were matured in: a) Control; b) VEGF 0-3h; c) Cysteamine 4-24h; d) VEGF 0-3h+Cysteamine 4-24h; and e) VEGF+Cysteamine 24h. The results showed that: i) VEGF did not alter GSH content in oocytes and cumulus cells; (ii) supplementation of 300 and 500ng/mL VEGF increased blastocyst yield; (iii) the presence of VEGF+Cysteamine simultaneously during 24h improved GSH content but not embryo development; and (iv) the presence of VEGF during the first 3h+Cysteamine from 4 to 24h increased GSH concentrations and subsequent embryo development. In conclusion, the addition of VEGF and Cysteamine in two sequential steps to maturation medium result in an improvement of cytoplasmic maturation, with a positive impact on oocyte developmental capacity by increasing the efficiency of in vitro blastocyst production. However, the effect was detrimental when both VEGF and Cysteamine were present during 24 of IVM.