Incidence of apoptosis in clone embryos and improved development by the treatment of donor somatic cells with putative apoptosis inhibitors

Abstract

This study was conducted to promote in vitro-development of clone embryos by the treatment of donor somatic cells with hemoglobin (Hb) and/or b-mercaptoethanol (ME), based on the analysis of apoptosis after somatic cell nuclear transfer (SCNT). Prospective, randomized study was conducted and, in vitro-matured bovine oocytes and fetal fibroblasts were provided for SCNT. In the first series of experiment, embryo apoptosis after SCNT was monitored by a terminal deoxynucleotidyl transferase-mediated d-UTP nick end-labeling assay. As results, apoptosis occurred more (P<0.05) frequently after SCNT than after in vitro-fertilization (IVF) of control treatment. Subsequently, donor somatic cells treated with Hb (1 mg/ml) and/or ME (10 mM) were provided for SCNT. Either Hb or ME greatly reduced apoptosis (0.0830.006 vs. 0.058–0.0680.005), while combined treatment did not. ME was more promotive than Hb; significant increases were found in morula compaction (86%), cell numbers of blastocyst (131.31.3 cells/blastocyst), and inner cell mass (31.90.8 cells/blastocyst) cell, and the ratio of inner cell mass to trophectodermal cell numbers (0.240.01). In conclusion, the treatment of donor somatic cells with ME or Hb could reduce apoptosis after SCNT, resulting improved preimplantation development.