Adição de proteína plasmática a associada à prenhez (PAPP-A) durante a maturação in vitro aumenta o IGF-1 biodisponível e modula o perfil transcricional de complexos cumulus-oócitos e embriões bovinos

Abstract

In this study we aimed to evaluate how PAPP-A addition during in vitro maturation affected the IGF-1 quantification, transcript abundance related to cumulus oocyte complexes (COCs) and blastocysts quality, embryonic yield, as well as post-warming survival. We matured COCs through a 24 h treatment of TCM199 serum-free medium, either with PAPP-A supplementation (100 ng/mL; PAPP-A group) or without (control). Maturation medium was collected for IGF-1 quantification, and matured COCs were used for in vitro fertilization and culturing. The PAPP-A group exhibited 1.27 times higher IGF-1 concentrations than control. A comparison of in vitro embryo production across the groups found no difference in cleavage rate, embryonic yield, and survival, 3 and 24 h post-cryopreservation. In PAPP-A oocytes, only TXNRD1 was up-regulated. However, in PAPP-A cumulus cells, VNN1 and HDAC2 were up-regulated, while AGPAT1, AGPAT9, FASN, CASP3, EGFR, HAS2, IMPDH1, and MTIF3 were down-regulated. Finally, in PAPP-A blastocysts, CPT2, CASP9, DNMT3A, TFAM, and KRT8 were up-regulated, while ATF4, CASP3, and IFITM3 were down-regulated. We concluded that PAPP-A addition increased IGF-1 but did not influence embryonic yield and survival. Nevertheless, elevated IGF-1 could improve embryo competence through modulating expression of genes involved with lipid metabolism, oocyte competence and apoptosis in COCs and blastocysts.