Lyophilized somatic cells direct embryonic development after whole cell intracytoplasmic injection into pig oocytes

The study investigated the feasibility of lyophilization for long-term preservation of somatic cells and embryonic development after whole cell intracytoplasmic injection (WCICI) into enucleated pig oocyte. Confluent cultured porcine fetal fibroblast (pFF) cells were lyophilized and stored at 4°C for at least 6 months. Results showed that compared to non-lyophilized control cells, lyophilized cells had drastically reduced cellular viability (P<0.01). WCICI of reconstituted lyophilized cells could support complete embryonic development. However, the rates of cleavage (64.7±2.7 vs. 43.5±4.7%) and blastocyst formation (18.2±0.6 vs. 10.2±1.6%) were lower than that of control (P<0.05). Total nuclei number per blastocyst (30.4±4.5 vs. 25.2±4.7) and intensity of acetylation at histone H3 (AcH3) protein (55.9±3.5 vs. 53.3±3.8) did not differ (P>0.05). The development ability of embryos, produced from lyophilized somatic cells, was further increased (19.5±2.4 vs. 10.2±1.6%; P<0.05) by treatment with trichostatin A (TSA) for 24h post-activation. These TSA-treated embryos also had AcH3 level comparable with in vitro fertilized embryos (63.1±3.2 vs. 69.9±1.3). In conclusion, our results suggest that lyophilized somatic cells can direct embryonic development up to blastocyst stage after WCICI into pig oocytes. Treatment of embryos, produced from lyophilized somatic cells, with TSA can further increase their in vitro developmental potential.