Fine structure of bovine blastocysts developed either in serum-free medium or in conventional co-culture with oviduct epithelial cells.
The ultrastructure of day 7 bovine blastocysts developed in vitro in either of two culture systems was compared with that of morphologically normal blastocytes collected non-surgically from superovulated cows on day 7 (Day 0 = day of insemination). The in vitro-embryos were obtained after culture of in vitro-matured and -fertilized oocytes either in a serum-free, cell-free medium (SFM, i.e. TCM 199 supplemented with BSA (10 mg/ml), insulin (5 micrograms/ml), transferrin (5 micrograms/ml) and selenium (5 ng/ml) or in a serum-supplemented medium (TCM 199 and 10% (v/v) oestrous cow serum) together with bovine oviduct epithelial cells (BOEC). Five of the 8 blastocysts developed in SFM fulfilled the criteria set for normal morphology of the in vivo-developed blastocytes. In contrast, 6 out of 8 blastocysts developed in co-culture with BOEC were classified as morphologically deviated, and only 2 reached the criteria for morphological normality. In vitro-developed blastocysts with deviated morphology showed a higher degree of cytoplasmic vacuolation, short, less developed cell-to-cell contacts between trophoblast as well as between inner cell mass (icm)-cells, less developed apical microvilli on the trophoblast and wide inter-cellular spaces. Additionally, numerous cytoplasmic vesicles, phagosomes, lipid droplets and hooded mitochondria were commonly present, both in trophoblast and in icm-cells. The results indicate that a high proportion of blastocysts developed in co-culture with BOEC were morphologically deviated compared to those cultured in medium where serum and somatic cells were replaced by BSA, insulin, transferrin and selenium.
Department of Obstetrics and Gynaecology, Faculty of Veterinary Medicine, Swedish University of Agricultural Sciences, Uppsala.
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M
Shamsuddin
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Rodriguez-Martinez
D000818:Animals; D001755:Blastocyst / Q000648:ultrastructure*; D002417:Cattle / Q000196:embryology*; D016895:Culture Media, Serum-Free; D004847:Epithelial Cells; D004848:Epithelium / Q000502:physiology; D005187:Fallopian Tubes / Q000166:cytology / Q000502:physiology*; D005260:Female; D008854:Microscopy, Electron
D016895:Culture Media, Serum-Free