Effect of demecolcine and nocodazole on the efficiency of chemically assisted removal of chromosomes and the developmental potential of nuclear transferred porcine oocytes.

Brief treatment of metaphase II (MII) stage porcine oocytes with 0.4 microg/mL demecolcine in the presence of 0.05 M sucrose produces a membrane protrusion that contains a condensed chromosome mass. The present study examined the optimal conditions for demecolcine and nocodazole treatment in chemically assisted removal of chromosomes. When matured oocytes were treated with 0.1-0.4 microg/mL demecolcine for 60 min or with 0.4 microg/mL demecolcine for 30 min or 3 microg/mL nocodazole for 30 or 60 min, more than 70% of oocytes had a membrane protrusion containing condensed chromosomes were located. There was no difference in the in vitro developmental potential of enucleated oocytes assisted by 0.1 and 0.4 microg/mL demecolcine or 3 microg/mL nocodazole that received porcine somatic cells. After transfer to 10 recipients, however, two of six recipients that received demecolcine-treated enucleated eggs produced four healthy cloned piglets, but none of the four recipients of nocodazole-treated enucleated eggs produced piglets. Further studies are required to increase the successful development to term because the proportion of live piglets was low (4/2, 672, 0.15%).