PP2A-B55α, a regulatory subunit of PP2A plays an important roles in regulating cell proliferation and survival. However, the functions for PP2A-B55α in mouse early embryo development is not clear. The objective of present were to investigate the expression patterns and to explore its biological function during mouse early development. Thetranscripts of PP2A-B55α were detected at all developmental stages in mouse embryo and decreased during embryo development. Immunostaining revealed that PP2A-B55α was present in both the nucleus and cytoplasm in early cleavage stage embryos. In the late embryonic development, PP2A-B55α was predominantly located in the cytoplasm. Knockdown (KD) of PP2A-B55α using double strand RNA not affect the proportion of cleaved embryos, but resulted in significantly decreased development to blastocyst stage and reduced total cell number in blastocyst. KD PP2A-B55α is able to induce sustained DNA damage and reduced the transcripts of non-homologous end joining (NHEJ) or homologous recombination (HR) pathways relative genes in mouse early embryo. KD PP2A-B55αcaused apoptosis and increase the transcripts of pro-apoptotic genes in blastocyst. Furthermore, The KDPP2A-B55α showed significantly lower cell proliferating rates (from 5-Bromo-deoxyuridineassayresults) in blastocysts and to talareas of out growth potential was decreased. These observation provide novel in sight into PP2A-B55α expression patterns in mouse early embryos and down-regulation of PP2A-B55α negatively impacted blastocyst development, total cell number, DNA damage, apoptosis, and proliferation and post-hatchingevents.

In the present study, we examined potential roles of glucose and pyruvate in nuclear and cytoplasmic maturation of porcine oocytes. In the presence and absence of 10% porcine follicular fluid (PFF), either 5.6 mM glucose or 2mM pyruvate effect on meiotic maturation and followed development ability. However, DOs doesn't take full advantage of the glucose in medium, only pyruvate can increase MII rate and follow early embryo development ability significance. COCs were matured with 200 uM pentose phosphate pathway (PPP) inhibitor (dehydroepiandrosterone, DHEA) or 2 μM glycolysis inhibitor (iodoacetate, IA), significantly lower levels of GHS in the DHEA an IA treated oocytes and the levels of ROS were higher significantly in the DHEA treated oocytes, treatment with DHEA significantly reduced the intra-oocyte ATP and NADPH level. Blastocysts from DHEA or IA treated group also presented higher apoptosis levels, meanwhile, the percentage of proliferating cells was dramatically lower than the non-treated group. In conclusion, our results suggest that 10% PFF promoted oocytes make full use of energy, glucose metabolism during in vitro maturation inseparable from the cumulus cells, PPP and glycolysis promoted porcine oocytes cytoplasmic maturation by supplying energy and reducing oxidative stress.