Presence of vascular endothelial growth factor during the first half of IVM improves the meiotic and developmental competence of porcine oocytes from small follicles

Abstract

The aim of the present study was to investigate the effect of vascular endothelial growth factor (VEGF) on the meiotic and developmental competence of porcine oocytes from small follicles (SF; 0.5-3 mm diameter). When cumulus-oocyte complexes (COCs) from medium-sized follicles (MF; 3-6 mm diameter) and SF were cultured for IVM, the maturation rates were significantly higher for oocytes from MF than SF. Concentrations of VEGF in the medium were significantly higher for COCs cultured from MF than SF. When COCs from SF were exposed to 200 ng mL -1 VEGF during the first 20 h of IVM, the maturation rate improved significantly and was similar to that of oocytes derived from MF. The fertilisability of oocytes was also significantly higher than that of VEGF-free SF controls. Following parthenogenetic activation, the blastocyst formation rate improved significantly when SF COC culture was supplemented with 200 ng mL -1 VEGF, with the rate similar to that of oocytes from MF. The results of the present study indicate that VEGF markedly improves the meiotic and developmental competence of oocytes derived from SF, especially at a concentration of 200 ng mL -1 during the first 20 h of IVM.Additional keyword: pig. T. M. T. Bui et al. Effect of VEGF on IVM of porcine oocytesOvaries contain a large number of small follicles, but the meiotic and developmental competence of oocytes from these follicles is quite low. In the present study we demonstrated that the addition of 200 ng mL -1 vascular endothelial growth factor to the IVM medium increased the maturation rate of porcine oocytes from small follicles and that blastocyst formation following parthenogenetic activation also increased. These findings may contribute to efficient animal production and human assisted reproductive technology.

Removal of cumulus cells around 20 h after the start of <i>in vitro</i> maturation improves the meiotic competence of porcine oocytes via reduction in cAMP and cGMP levels

“…Our study confirms previous results [9, 10, 18, 19] that show that MF-derived oocytes have higher meiotic and developmental competences in vitro than SF-derived oocytes. The developmental competence of oocytes appears to be acquired during the final process of follicular development through an interaction with their companion somatic cells [20].…”

“…We have shown that the number of cumulus cells surrounding an SF-derived oocyte was significantly lower than a MF-derived oocytes and that supplementation of the IVM media with a cumulus cell mass significantly improved both the ooplasmic diameter and the meiotic competence of the oocytes to reach the metaphase-II stage following IVM [21]. We have also suggested that differences in the levels of vascular endothelial growth factor secreted from cumulus cells reflects the meiotic and developmental competences of SF-derived porcine oocytes and supplementation of IVM medium with vascular endothelial growth factor improves their competence [19]. Since it is not well known if the interaction between cumulus cells affects intracellular cAMP and cGMP levels, which are well known to regulate meiotic resumption in oocytes [22], or if the interaction is similar between SF- and MF-derived oocytes during IVM, we examined the effect of denuding oocytes 20 h after the start of IVM in our standard culture system [3].…”

Circular RNA profiling in the oocyte and cumulus cells reveals that circARMC4 is essential for porcine oocyte maturation

“…For instance, both WEE2 enriched in the female meiotic division and cAMP molecules have been shown to inhibit the resumption of oocyte meiosis in several species [47, 48]. In contrast, VEGF supplement significantly improved maturation rate of oocytes in cattle [49], sheep [50] and pigs [51]. Altogether, we thus reasoned that DECs identified in oocytes could positively or negatively regulate porcine oocyte meiotic maturation in a synergistic manner.…”

Circular RNA profiling in the oocyte and cumulus cells reveals thatcircARMC4is essential for porcine oocyte maturation

“…For instance, both WEE2 enriched in the female meiotic division and cAMP molecules have been shown to inhibit the resumption of oocyte meiosis in several species (Hanna et al, 2010; Ramos Leal et al, 2018). In contrast, VEGF supplement significantly improved maturation rate of oocytes in cattle (Luo et al, 2002), sheep (Yan et al, 2012) and pigs (Bui et al, 2017). Altogether, we thus reasoned that DECs identified in the oocyte could positively or negatively regulate porcine oocyte meiotic maturation in a synergistic manner.…”