Equine non-invasive time-lapse imaging and blastocyst development

Abstract

In this study we examined the timeline of mitotic events of invitro-produced equine embryos that progressed to blastocyst stage using non-invasive time-lapse microscopy (TLM). Intracytoplasmic sperm injection (ICSI) embryos were cultured using a self-contained imaging incubator system (Miri®TL; Esco Technologies) that captured brightfield images at 5-min intervals that were then generated into video for retrospective analysis. For all embryos that progressed to the blastocyst stage, the initial event of extrusion of acellular debris preceded all first cleavages and occurred at mean (±s.e.m.) time of 20.0±1.1h after ICSI, whereas 19 of 24 embryos that did not reach the blastocyst stage demonstrated debris extrusion that occurred at 23.8±1.1h, on average 4h longer for this initial premitotic event (P<0.05). Embryos that failed to reach the blastocyst stage demonstrated a 4-h delay compared with those that reached the blastocyst stage to reach the 2-cell stage (P<0.05). All embryos that reached the blastocyst stage expressed pulsation of the blastocyst with visible expansion and contraction at approximate 10-min intervals, or five to six times per hour. Using a logit probability method, we determined that 2- and 8-cell stage embryos could reasonably predict which embryos progressed to the blastocyst stage. Together, the results indicate that TLM for equine embryo development is a dynamic tool with promise for predicting successful embryo development.

Gene expression of equine cumulus cells during in vitro and in vivo oocyte maturation

“…It has been suggested that the osmotic pressure, gap junctions in between TE and inner cell mass (ICM), ion and water channels and pumps, and contractile proteins are involved in this event [6][7][8][9] . Previously, our laboratory reported embryo pulsing being observed in in vitro -produced equine embryos [10] . Similarly, Lewis et al, reported the presence of pulsing in equine embryos using timelapse imaging [11] .…”

Clinical perspective: The perils, pitfalls and pride of developing an equine in vitro fertilisation (IVF) laboratory in private practice

“…Both CO 2 and tri-gas box incubators were initially purchased for oocyte maturation and culture respectively. Benchtop incubators have since been obtained for culturing embryos; these incubators have grown in ubiquity and appear to provide superior performance relative to traditional box incubators (Gelo et al, 2019;Martino et al, 2019;Meyers et al, 2019). Also purchased was a biosafety Given the many moving parts involved in starting the laboratory, media preparation proved to be a time-consuming and mistake-laden task, especially when a designated technician was not available.…”

The Mare: A Pertinent Model for Human Assisted Reproductive Technologies?

“…In humans, in recent years, many tools have been developed to assist medical teams in this selection, while in horses, the quality assessment of cultured embryos is at its beginning. Methods can be invasive, such as embryo biopsy for pre-implantation genetic testing [ 124 , 157 , 158 ], or non-invasive, such as embryo monitoring by time-lapse imaging [ 159 , 160 , 161 , 162 , 163 ], metabolomics, or aneuploidy diagnosis on spent culture media (niPGT–A) [ 164 ]. These different techniques present different sensitivities, specificities, and acceptability, but have allowed to better control early embryonic development, to refine the criteria for the choice of the embryo to be transferred, and to promote single embryo transfer and thus considerably reduce the risks of multiple pregnancies (see below).…”