The effect of pre-maturation culture using phosphodiesterase type 3 inhibitor and insulin, transferrin and selenium on nuclear and cytoplasmic maturation of bovine oocytes.

This study aims to evaluate if a pre-maturation culture (PMC) using cilostamide as a meiotic inhibitor in combination with insulin, transferrin and selenium (ITS) for 8 or 24 h increases in vitro embryo production. To evaluate the effects of PMC on embryo development, cleavage rate, blastocyst rate, embryo size and total cell number were determined. When cilostamide (20 M) was used in PMC for 8 or 24 h, 98% of oocytes were maintained in germinal vesicles. Although the majority of oocytes resumed meiosis after meiotic arrest, the cleavage and blastocyst rates were lower than the control (P 0.05) to the control. The deleterious effect of 20 M cilostamide treatment for 24 h on a PMC was confirmed by lower cumulus cell viability, determined by trypan blue staining, in that group compared with the other groups. A lower concentration (10 M) and shorter exposure time (8 h) minimized that effect but did not improve embryo production. More studies should be performed to determine th

Effects of Prostaglandins E2 and F2alpha on the in vitro maturation of bovine oocytes.

We aimed to elucidate the effects of PGE2 and PGF2a on the in vitro maturation (IVM) of bovine oocytes. First, cumulus-oocyte complexes were matured in the media supplemented with or without PGE2, PGF2a, or PGE2 plus PGF2a for the final 24, 12, or 6 h of culture. Then, the cumulus-oocyte complexes were matured in the absence or presence of a PG endoperoxide synthase 2 (PTGS2) enzyme inhibitor (NS398) supplemented with PGE2, PGF2a, or PGE2 plus PGF2a. Finally, the expression of genes associated with PGs activity in cumulus cells (PTGS2, PG E-synthase-1 [PTGES1], and aldo-keto reductase 1 [AKR1B1]) or oocytes (receptors for PGE2 [PTGER2] and PGF2a [PTGFR]) of different competencies was quantified. Supplementation of the IVM medium with PGs did not improve in vitro embryo production or embryo quality (P > 0.05). During maturation, the relative abundance of PTGS2 transcripts increased (P < 0.05) only in the less-competent group, whereas those of PTGES1 increased in the less-competent and in the more-competent groups. Conversely, AKR1B1 expression decreased only in the less-competent group (P < 0.05). Receptors for the PGE2 and PGF2a genes were very low or undetectable in oocytes. In conclusion, PGE2 and PGF2a are not recommended for media supplementation during maturation because they have no effect on embryo development. Although genes related to PGs activity are differentially expressed in cumulus cells of cumulus-oocyte complexes of different competence during maturation, the expression of PGE2 and PGF2a receptor genes was either not detectable or was detected at low levels in oocytes