Science & Technology

Although laboratory procedures for in vitro bovine embryo production have improved immensely, developmental capacity following fertilization is still limited. Closer replication of the in vivo environment in in vitro maturation systems may improve embryo production while providing insight into the relative importance of the follicle fluid components for in vivo oocyte competence (especially steroid hormones). Therefore, the objective of this study was to investigate the impact of follicle size and relative estradiol and progesterone concentrations on oocyte maturation and early embryo development following follicle fluid exposure during maturation in vitro. Follicle fluid was collected via needle aspiration from small (2-5 mm diameter) and large (10-20 mm diameter) follicles and pooled according to size. Cumulus-oocyte complexes (n=4,004) were matured in groups of 15 in 50 l OMM drops for 21 h. After 21 h maturation, oocytes were subjected to in vitro fertilization and in vitro culture. Cleavage was evaluated at d 3 post-fertilization, and blastocysts were evaluated at d 8 post-fertilization. Cleavage rates were affected by treatment (P<0.01). The C+ treatment yielded the highest cleavage rate, and this rate exceeded the C- and all follicle fluid treatments (P<0.05). Blastocyst rates were also affected by treatment (P<0.01). The addition of estradiol alone or with progesterone did not support early embryonic development, while the addition of progesterone alone improved development and returned blastocyst development rates to the same level as the control treatment. The cause of the inhibitory effect of the estradiol-progesterone combination is still unknown, and future research investigating these mechanisms would further the understanding of the follicular microenvironment in which the oocyte undergoes final maturation.

We are honored to have as our guest faculty for the evening Drs. Rupen Shah, David Kwon and David McVinnie, of Henry Ford Hospital, Detroit, MI., who will guide us through an agenda centered on the topic of Small Bowel and Pancreatic Neuroendocrine Neoplasms: A case-based Discussion.