title: Improved embryo development with decreased apoptosis in blastomeres after the treatment of cloned bovine embryos with beta-mercaptoethanol and hemoglobin.
abstract: In preliminary experiments, the treatment of donor somatic cells with beta-mercaptoethanol (ME) or hemoglobin (Hb) improved in vitro-development of bovine cloned embryos. This study was subsequently evaluated whether the exposure to Hb and/or ME during in vitro-maturation or embryo culture could further promote the development of embryos cloned with ME-treated donor cells. A prospective, randomized study was conducted and, embryo development, cell number, and apoptosis in blastocysts were monitored. A significant (P < 0.05) effect was found after the combined treatment of cloned embryos with Hb (1 microg/ml) and ME (10 microM); the development of morulae (53 vs. 35%) was greatly improved, which resulted in enhanced blastocyst formation (38%). However, cell number and apoptosis in blastocysts were predominantly affected by ME rather than Hb; a significant increase in total cell number of blastomeres (142-154 vs. 123 cells/embryo), inner cell mass (ICM) (39-41 vs. 27), and trophectoderm (TE) (103-114 vs. 98), and the ratio of ICM to TE cell number (0.26-0.27 vs. 0.22) was found. Also, the apoptosis index indicating the ratio of apoptotic cell to normal blastomere number was greatly reduced after ME treatments (0.85 vs. 0.056-0.069). When embryos cloned with ME-treated cells were cultured in Hb + ME-containing medium, any of the treatments to recipient oocytes before enucleation did not further promote the development. In conclusion, combined treatment of cloned embryos with Hb + ME not only improved in vitro-development but also decreased blastomere apoptosis. The use of ME-treated donor cells and the culture of cloned embryos in Hb + ME-containing medium yielded the optimal results for promoting the production of blastocysts with improved quality.
authors.affiliation: School of Agricultural Biotechnology, Seoul National University, Seoul, Korea.
authors.forename: Eul Soon
authors.initials: ES
authors.lastname: Park
authors.forename: Woo Suk
authors.initials: WS
authors.lastname: Hwang
authors.forename: Sung Keun
authors.initials: SK
authors.lastname: Kang
authors.forename: Byeong Chun
authors.initials: BC
authors.lastname: Lee
authors.forename: Jae Yong
authors.initials: JY
authors.lastname: Han
authors.forename: Jeong Mook
authors.initials: JM
authors.lastname: Lim
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001755:Blastocyst / Q000166:cytology / Q000187:drug effects; D001757:Blastomeres / Q000166:cytology / Q000187:drug effects; D002417:Cattle; D019976:Cloning, Organism; D047108:Embryonic Development / Q000187:drug effects*; D005260:Female; D006454:Hemoglobins / Q000494:pharmacology*; D066298:In Vitro Techniques; D008623:Mercaptoethanol / Q000494:pharmacology*; D053652:Nuclear Transfer Techniques
chemical_list: D006454:Hemoglobins; D008623:Mercaptoethanol