Development of reconstituted pig embryos by nuclear transfer of cultured cumulus cells

Abstract

This study tested the effects of oocyte collection method, activation protocoland maturational age of recipient oocytes on thein vitro development of nuclear transfer embryosreconstructed with cultured cumulus cells. Cumulus cells synchronized inG<emph type="8">0/G<emph type="8">1 phase byserum-starvation culture were transferred into enucleated oocytes that werecollected by aspiration or dissection method and cultured for 33 or 44 h.Reconstituted embryos were activated with a combination of calcium ionophoreA23187 or electric pulse and cycloheximide (CHXM), and cultured for 6 days.Oocyte collection methods, activation treatment in the presence ofcytochalasin B and activation protocols did not affect the developmental rateof embryos reconstituted with 44-h-matured recipients. However, thedevelopment of embryos reconstituted with 33-h-matured recipients wassignificantly improved (P&lt;0.05) by activation withthe combination of electric pulse and CHXM. The present study shows thatreconstituted porcine embryos derived from cultured cumulus cells can developto the blastocyst stage, and that their development can be improved byreconstruction with young oocyte cytoplasts following activation with acombination of electric pulse and CHXM.