time-lapse胚胎即時監測顯示，囊胚期胚胎在最後膨脹&破殼而出前會有2-4小時短暫收縮&囊胚腔縮小之現象

Reprod Biomed Online. 2016 Sep 12. pii: S1472-6483(16)30503-X. doi: 10.1016/j.rbmo.2016.08.020. [Epub ahead of print]

Morphokinetics of human blastocyst expansion in vitro.

Huang TT1, Chinn K2, Kosasa T3, Ahn HJ4, Kessel B3.

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Abstract

Time-lapse imaging offers new tools to study dynamic processes of development such as blastocyst formation and expansion. This study quantitatively describes expansion in human blastocysts from donated oocytes. Measurements of hourly interval rate of changes in the blastocoel cross-sectional area revealed oscillatory pulses having 2-4 h periodicities. Two types of oscillations were distinguished. An E-Type ('expansion') had positive peak and positive or slightly negative trough interval rate of change values, and these characterized most of the expansion period. A C-type ('contraction') represented an infrequent but notable contraction of the blastocoel with loss of blastocoel fluid. These were reversible within 2-4 h in both groups and followed by further expansion. Therefore, oscillatory pulses are an intrinsic property of the trophectoderm. The zona seems to variably dampen the amplitude of these pulses. Expansion kinetics were compared between blastocysts with known positive (KID+) or negative (KID-) implantation outcomes. Regression analysis suggests that expansion may be relatively restricted in KID- embryos blastulating at relatively later times. These data extend observations in other mammalian systems and may provide information useful for clinical selection algorithms.