Development of Tetraploid and Tetraploid/Diploid Mosaic Mouse Embryos Induced by Protein Kinase C Activators

Effects of protein kinase C (PKC) activators were investigated in mouse embryos during the developmental stage before compaction on cell division and subsequent development. Two-cell stage embryos were cultured for 24 h with phorbol 12-myristate 13-acetate (PMA; 0.1 or 1 nM) or 1 oleoyl 2-acetyl-sn-glycerol (OAG; 10 or 100 μM). PMA- and OAG-treatment inhibited cell division and embryos with binucleate blastomeres were produced in a dose dependent manner. The embryos in groups of 1 nM PMA and 100 μM OAG which were allowed to develop into the blastocyst stage had few nuclei and thin or no inner cell mass (ICM)-like structures. These blastocysts were transferred to the uterus of recipients. Consequently, some of the transferred embryos in groups of 1 nM PMA and 100 μM OAG implanted, but most of them had died by day 17.5 of pregnancy. In assessment of blastocyst outgrowth, the frequencies of outgrowths without ICM structure significantly increased in groups of 1 nM PMA and 100 μM OAG compared with the control. The present study indicates that application of PKC activators for 24 h from the 2-cell stage to mouse embryos leads to the production of tetraploid and tetraploid/diploid mosaic embryos, extreme reduction of embryonic cell number, and consequently the post-blastocyst development is obstructed in vivo and in vitro.