In this article, we focused on the impact of precisely chemically modified FLI maturation medium enriched with fibroblast growth factor 2 (FGF2), leukemia inhibitory factor (LIF), insulin-like growth factor 1 (IGF1), and polyvinyl alcohol (PVA) and its potential to improve the efficiency of in vitro production of porcine embryos. We hypothesized that enhancing the composition of the maturation medium could result in an elevated production of embryos in vitro and can affect EGA. FLI medium resulted in a significantly higher rate of oocyte blastocyst maturation and formation compared to the control DMEM medium. In addition, immunocytochemical labelling confirmed the detection of UBF in 4-cell FLI parthenogenic embryos, suggesting similarities with natural embryo development. Through RNAseq analysis, upregulated genes present in 4-cell FLI embryos were found to play key roles in important biological processes such as cell proliferation, cell differentiation, and transcriptional regulation. Based on our findings, we demonstrated the positive influence of FLI medium in the evaluation of in vitro embryo production, EGA detection, transcriptomic and proteomic profile, which was confirmed by the positive activation of the embryonal genome in the 4-cell stage of parthenogenetically activated embryos.

• MeSH
• Blastocyst drug effects   metabolism   MeSH
• Fertilization in Vitro MeSH
• Fibroblast Growth Factor 2 * pharmacology   MeSH
• Insulin-Like Growth Factor I * pharmacology   MeSH
• Culture Media * chemistry   pharmacology   MeSH
• Leukemia Inhibitory Factor * pharmacology   MeSH
• Oocytes MeSH
• Swine embryology   genetics   MeSH
• Proteomics MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Fibroblast Growth Factor 2 * MeSH
• Insulin-Like Growth Factor I * MeSH
• Culture Media * MeSH
• Leukemia Inhibitory Factor * MeSH

BACKGROUND: Oocytes of large animal species isolated from small ovarian follicles (< 2 mm) are less competent to support early embryonic development after in vitro maturation and fertilization than their counterparts isolated from medium-sized and preovulatory follicles. This study aimed to assess the effect of a new maturation medium containing FGF2, LIF, and IGF1 (FLI medium) on the meiotic and developmental competence of pig cumulus-oocytes complexes (COCs) derived from the small and medium-sized follicles. METHODS: The growing oocytes were isolated from 1 to 2 (small follicle; SF) and the fully-grown ones from 3 to 6 (large follicle; LF) mm follicles and matured in a control M199 medium with gonadotropins and EGF and the FLI medium enriched by the triplet of growth factors. The matured oocytes were parthenogenetically activated and cultured to the blastocyst stage. Chromatin configuration before and during the culture and MAP kinase activity were assessed in the oocytes. Finally, the expression of cumulus cell genes previously identified as markers of oocyte quality was assessed. RESULTS: The maturation and blastocyst rates of oocytes gained from LF were significantly higher than that from SF in the control medium. In contrast, similar proportions of oocytes from LF and SF completed meiosis and developed to blastocysts when cultured in FLI. Most of the oocytes freshly isolated from SF possessed germinal vesicles with fine filaments of chromatin (GV0) or chromatin surrounding the nucleolus (GVI; 30%); the oocytes from LF were mainly in GVI (or GVII) exhibiting a few small lumps of chromatin beneath the nuclear membrane. When cultured in the FLI medium for 16 h, an acceleration of the course of maturation in oocytes both from SF and LF compared to the control medium was observed and a remarkable synchrony in the course of chromatin remodeling was noticed in oocytes from SF and LF. CONCLUSIONS: This work demonstrates that the enrichment of culture medium by FGF2, LIF, and IGF1 can enhance the meiotic and developmental competence of not only fully-grown, but also growing pig oocytes and significantly thus expanding the number of oocytes available for various assisted reproductive technology applications.

• Keywords
• Chromatin configuration, Developmental potential, Follicle size, Gene expression, Growth factors, MAPK activation, Oocyte maturation,
• MeSH
• Chromatin metabolism   MeSH
• Fibroblast Growth Factor 2 * pharmacology   metabolism   MeSH
• In Vitro Oocyte Maturation Techniques * MeSH
• Meiosis MeSH
• Oocytes metabolism   MeSH
• Ovarian Follicle MeSH
• Swine MeSH
• Pregnancy MeSH
• Animals MeSH
• Check Tag
• Pregnancy MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Chromatin MeSH
• Fibroblast Growth Factor 2 * MeSH