69 EFFECTS OF CELL TYPE, PRE-ACTIVATION PROTOCOL, AND CULTURE CONDITIONS ON DEVELOPMENT OF PORCINE HANDMADE CLONED EMBRYOS
J. C. Mezzalira A , L. U. Ohlweiler A , A. Massie B , E. Monaco B , E. P. Silva B , Y. Yuan B , A. Mezzalira B , M. Bertolini A , R. L. Krisher B and M. B. Wheeler BA Center of Agronomy and Agroveterinary Sciences, Santa Catarina State University, Lages, SC, Brazil;
B University of Illinois at Urbana-Champaign, Urbana, IL, USA
Reproduction, Fertility and Development 22(1) 193-193 https://doi.org/10.1071/RDv22n1Ab69
Published: 8 December 2009
Abstract
Despite the rather successful and widespread use of cloning in various species, distinct cell types from the same species and even the same genotype display differences in blastocyst yield. Moreover, variations in the protocol for embryo production can influence development to the blastocyst stage and subsequent fetal development. The aim of this study was to evaluate the effect of 2 cell types and 2 embryo pre-activation protocols with or without the presence of FCS in the in vitro culture medium on development of handmade pig cloned embryos to the blastocyst stage. Cumulus-oocyte complexes recovered from sow ovaries were in vitro-matured for 38 to 40 h. Denuded matured oocytes selected by the presence of a polar body had the zona pellucida removed in a 0.2% protease HEPES-buffered solution +25% FCS, followed by manual bisection and UV screening of enucleated halves using Hoechst stain. Clone embryo reconstruction was performed using a phytohemoagglutinin solution to adhere 2 cytoplasts and a somatic cell. Adipocyte-derived mesenchymal stem cells (ADMSC) from a Yorkshire pig or granulosa cells (GC) from an Ossabaw pig were used as nuclear donors. Following electrical fusion, couplets were pretreated with a brief exposure to cytochalasin B (CB) or cytochalasin B + cycloheximide (CB+CX) in the presence of serum before the electrical activation (Naruse et al. 2007 Theriogenology 68, 709-716; Du et al. 2009 Reprod. Fertil. Dev. 21, 114). Activated embryos were in vitro-cultured in the well of the well (WOW) system, with 2 embryos per microwell, for 7 days in PZM-3 medium +0.3% BSA in the presence (FBS+) or absence (FBS-) of 10% FCS. Cleavage (Day 2, chi-square test) and blastocyst (Day 7, Fisher test) rates, on a per WOW basis, were compared for a level of significance of 5%. Our preliminary data indicate that the presence of serum in the IVC affected cleavage and blastocyst yield in a cell-type-dependent manner. The presence of serum enhanced the blastocyst yield for ADMSC, whereas for GC, only the absence of serum allowed any blastocyst development. The cell type and the pre-activation protocol did not appear to affect cleavage and embryo development to the blastocyst stage. Despite the low number of replications, our results reinforce the importance of optimizing the embryo production system taking into consideration the individual requirements for distinct cell types, procedures, and culture conditions.
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