Conditioned medium increases the polyploid cell composition of bovine somatic cell nuclear-transferred blastocysts.
The effects of bovine cumulus cell-conditioned medium on cloned bovine embryonic development and subsequent chromosome complement were examined using an air-dry procedure. Conditioned media were prepared using CR1aa supplemented with either fetal bovine serum (FBS) or bovine serum albumin (BSA). Nuclear-transferred embryos were reconstructed with nuclei from cumulus cells. Similar cleavage, morula, and blastocyst development was observed in conditioned media groups compared with the co-culture group. No differences (P > 0.05) were observed in the composition of blastocyst chromosomes after co-culture in different media, either with or without starvation of donor cells. The overall diploid blastocyst rate ranged from 75% to 84%. Chromosomal complement of blastocysts, however, was very different between conditioned medium and co-culture treatments. Overall incidence of chromosomal anomalies was 40% in conditioned medium, which was significantly higher (P < 0.001) than the co-culture group (20%). Moreover, a higher incidence (P < 0.05) of chromosomally abnormal blastocysts (41.5%) was observed after culture with FBS-containing conditioned medium than those cultured in BSA-containing conditioned medium (31.4%). No diploid improvement was observed after exchange of the culture system from conditioned medium to co-culture, or from co-culture to conditioned medium after the first 72 h of culture. The results of this study also indicated that the overall cell number was much lower (P < 0.01) in blastocysts with chromosomal abnormalities than those with a normal diploid state. We have concluded that medium conditioned with bovine cumulus cells increases the incidence of chromosomal anomalies in nuclear reconstructed embryos.
Li
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GP
Department of Animal, Dairy and Veterinary Sciences, Utah State University, Logan, Utah 84322, USA.
White
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Aston
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Meerdo
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LN
Bunch
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D000818:Animals; D001755:Blastocyst / Q000166:cytology*; D002417:Cattle; D019976:Cloning, Organism; D018920:Coculture Techniques; D017077:Culture Media, Conditioned; D005260:Female; D005312:Fetal Blood; D053652:Nuclear Transfer Techniques; D009865:Oocytes / Q000378:metabolism; D011123:Polyploidy; D012710:Serum Albumin, Bovine
D017077:Culture Media, Conditioned; D012710:Serum Albumin, Bovine