51 SCRIPTAID AND MG132 IMPROVE DEVELOPMENT OF PORCINE EMBRYOS RECONSTRUCTED BY SOMATIC CELL NUCLEAR TRANSFER

Abstract

Nuclear transfer efficiency in pigs and other large animal species is low. Previous studies have shown that histone deacetylase inhibitor (Scriptaid) and proteasomal inhibitor (MG132) treatment of somatic cell nuclear transfer (SCNT) pig embryos enhances blastocyst formation and pregnancy. The current experiment was carried out to determine the effects of combined MG132 and Scriptaid treatment on early development of cloned pig embryos reconstituted by SCNT. A total of 328 sow oocytes procured from ART (Madison, WI, USA) were reconstructed using α-1,3-Galactosyltransferase knockout hDAF transgenic pig fetal-derived fibroblast cells. Immediately after electrofusion and activation, SCNT oocytes were treated with 0, 1, or 10 μM MG132 for 2 h and then treated with 500 nM Scriptaid for another 16 h. The SCNT embryos were washed and cultured in Porcine Zygote Medium 3 for 7 days. Percent cleavage was determined on Day 2, and blastocyst formation and cell number were determined on Day 7. The experiment was repreated 8 times. There was no difference (P > 0.05) in percent cleavage (57.9 to 66.7%), or cell number (25.5 to 30.6) among the 3 groups. Interestingly, while there was no difference in the percent blastocyst between the 1 μM and 0 μM MG132 treatment groups, more oocytes from the 1 μM MG132 group developed into blastocysts than in the 10 μM MG132 group (25.1 ± 4.6% v. 12.9 ± 3.3%; P = 0.045). Further research will be conducted to transfer these embryos to surrogate gilts to determine the true developmental competence of these embryos.