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Influence of different oxygen concentrations on mouse embryo development using time-lapse-imaging
20 September 2018 (online)
Estimate the influence of oxygen concentration on embryo development in ART using mouse embryo assay and morphokinetics provided by time lapse imaging.
Material and methods:
Female mice (BI6/CBAca) were sacrificed and zygotes were isolated 20 hours after mating. 314 zygotes were arranged randomly into three parallel groups consisted of atmospheric oxygen concentration (21%-high group) (n = 93), low oxygen (5%) (n = 129), and mixed (7% from day 1 to 2 and 2% from day 3 to 5) (n = 92). Zygotes were cultured in Primovision micro-well culture dishes using GTL Medium (Vitrolife) and were observed in the Primovision time-lapse system. All statistical analyses were performed using the R program.
Blastocyst rate at 120 hours in mixed group (91.3%) was significantly increased compared to high (76.3%) and low group (74.4%, p= 0.009 and 0.001), respectively. Blastocyst size was enlarged in mixed group (p < 0.001 compared to high and low group). Morphokinetics showed significantly faster cell division of mixed group in almost every cleavage stage compared to high or low groups.
This study demonstrated that the oxygen concentrations, which mimic the changes in the oviduct (7% from day 1 to day 2) and uterus (2% from day 3 to day 5), significantly improved the blastocyst rate, the blastocyst size and speeded up time to cell divisions compared to routinely used conditions. Time lapse imaging is a highly sensitive measure to evaluate embryo development and changes in culture conditions.