Rescue of mouse embryos from 2-cell blocks by microinjection of maturation promoting factor

Objective: To examine the rescue of mouse embryos from 2-cell blocks by the microinjection of maturation promoting factor (MPF) extracted from matured Xenopus eggs into one of the blastomeres of 2-cell stage mouse embryos. Design: Controlled laboratory study. Setting: First Department of Obstetrics and Gynecology, Toho University School of Medicine, Tokyo, Japan. Animal(s): Eight- to 10-week-old female Crj:CD-1(ICR) mice. Intervention(s): One of the blastomeres of the mouse 2-cell embryos was injected with MPF (MI group) or mHTF medium (MED group) at 28–32 hours after insemination. Main Outcome Measure(s): The developmental rate to blastocyst. Result(s): The developmental rate to blastocyst in the MI group (48.0%) was significantly higher than that in the MED group (0%). Conclusion(s): The 2-cell block was specifically rescued by the microinjection of MPF and not by the insertion of pipettes.