Purpose: A mouse model was used to evaluate the consequences of partial cytoplasm removal, which mimics the consequence of human early embryo fragmentation, at the one-cell stage on embryonic development to the morula and blastocyst stages.
Results: Opening the zona pellucida at the zygote stage has no detrimental effect on the number of differentiated or total cells at morula/blastocyst stage. However, reduced cytoplasm significantly affects the number of inner cell mass cells, 21.7 (10% cytoplasm removed) vs 27.6 (control) and 15.1 (20% cytoplasm removed) vs 24.7 (control).
Conclusions: The contribution of cytoplasm of maternal origin is critical to early embryonic development.