Donor and Recipient Rat Strains Affect Full-Term Development of One-Cell Zygotes Cultured to Morulae/Blastqcysts

摘要

The present study was conducted to examine the developmental potential to offspring of rat embryos cultured from 1-cell to morula/blastocyst stage, Pronuclear zygotes from Wistar x Wistar or (SD x DA) x Wistar strains were cultured in modified rat 1-cell embryo culture medium (mRlECM) for 96 h in 5% CO_2 in air at 37 C. The proportion of the 3-way cross hybrid zygotes developing into morula/blastocyst stage (74%) was higher than that of the Wistar zygotes (66%). Day-5 morulae/ blastocysts developed in vitro were transferred into Day-3 or -4 pseudopregnant recipients of Wistar or SD x DA strain. The transfer of cultured embryos resulted in the birth of offspring at 13-59%, while that of non-cultured control blastocysts showed birth rates of 35-65% The best offspring rate of cultured embryos (59%) was obtained when the hybrid 1-cell zygotes were cultured in mRlECM medium and transferred into the 2-days earlier uteri of SD x DA recipients. These results suggest that genetic background of recipients aswell as donors is a possible factor affecting full-term development of rat morulae/blastocysts derived from 1-cell stage zygotes cultured in vitro.