275 DERIVATION OF PLURIPOTENT CELL LINES FROM PIG EMBRYOS: IN VITRO-FERTILIZED V. PARTHENOGENTIC ACTIVATION

The establishment of porcine pluripotent ES cell lines would be an exciting and novel tool for animal biotechnology, such as cloning and transgenesis. Furthermore, it would represent a useful model for biomedical research, cell therapy, xenotransplantation as well as developmental biology research. However, in spite of several studies, no conclusive results have been obtained and a number of technical questions are still to be answered in order to derive genuine ES cells in the pig. Here we report the results obtained in our laboratory aimed at comparing IVF v. parthenogenetic embryos as a source for the establishment of putative ES cells. Oocytes were divided in two groups and subjected to IVF or parthenogenetically activated with ionomicyn and 6-DMAP. They were cultured in NCSU for 7 days and then subjected to immuno-surgery. Inner cell mass were plated onto inactivated STO feeder cells and outgrowth formation was monitored. Cells were passaged to a new STO monolayer every 7 days. Assessment of pluripotency markers was carried out both by RT-PCR and immunocytochemical analysis at every passage for up to 22 passages. Telomerase activity was measured every 5 passages. The results indicate that parthenogenetic embryos, although less resilient than IVF embryos to immuno-surgery, have a significantly greater ability to generate outgrowths and stable cell lines. Moreover, 77% of the 39 parthenogenetic lines derived v. only 33% of the IVF ones expressed pluripotency markers and displayed high telomerase activity. Altogether our findings are consistent with data obtained in the human where the efficiency to derive hES cell lines from parthenogenetic blastocysts appears greater as compared with regular blastocysts from IVF embryos (Cheng L 2008 Cell Research 18, 215–217). Table 1. Supported by: Prin 2005, 2006.