236 effect of cyclic adenosine monophosphate modulator regulators in association with bmp15 on bovine embryo development in vitro

Abstract

BMP15 is a promising peptide to improve oocyte competence; also, addition of cyclic adenosine monophosphate modulator (cAMP) regulators prevents spontaneous maturation in vitro and promotes embryo development. We aimed to assess embryo development after prematuration [pre-in vitro maturation (IVM)] with IBMX and Forskolin (FSK) and maturation in the presence or absence of a purified pro mature region of BMP15. Immature cumulus-oocyte complexes (COC) were cultured in vitroMat (IVF Vet Solutions, Adelaide, Australia) plus 4mgmL(-1) fatty acid free-BSA and rhFSH (0.1IUmL(-1)), then divided into the following treatment groups: 1) spontaneous IVM: 24h of IVM; 2) spontaneous IVM+BMP15: 24h of IVM in the presence of BMP15 (100ngmL(-1)); 3) Pre 2 h: pretreatment with IBMX (500µM; Sigma-Aldrich) and FSK (100µM; Sigma-Aldrich) for 2h following 24h maturation; and 4) Pre 2 h+BMP15: pretreatment with IBMX and FSK for 2h following 24h maturation in the presence of BMP15 (100ngmL(-1)). After maturation, oocytes were inseminated and zygotes were cultured for 5 days in VitroCleave (IVF Vet Solutions, Adelaide, Australia) and transferred into VitroBlast (IVF Vet Solutions, Adelaide, Australia) until blastocyst assessment (Days 7 and 8). Zona-intact embryos were retrieved to assess differential staining of trophectoderm and inner cell mass. Data were transformed into a logarithm and analysed by 1-way ANOVA and post hoc least significant difference using SigmaStat software (SPSS Inc., San Jose, CA, USA; P<0.05). There was no difference among groups on cleavage rates or blastocyst rates at Day 7; however, both Pre 2h treatments increase hatched blastocyst rates at Day 8 of embryo development (Table 1). Supplementation with BMP15 increased total blastocyst rates at Day 8, regardless of pretreatment with IBMX+FSK (Table 1). Our data demonstrate that embryos from oocytes matured in the presence of BMP15 or pretreated with IBMX+FSK increase trophectoderm and total cell numbers; however, no differences were observed for inner cell mass. We conclude that Pre 2h treatment or BMP15 increase embryo development; however, no effect of cAMP regulators in association with BMP15 on embryo development was observed.