The effect of serum fractions on embryo growth.

In order to determine optimal culture conditions for embryos, human fetal cord serum (HCS) small- and large-molecular-weight fractions of HCS, and human serum albumin were employed as media supplements. In the first phase, embryos were cultured with the various protein supplements for 96 hours and observed morphologically every 24 hours. In the second phase, embryos were cultured with the various protein supplements and 5-bromo-2-deoxyuridine for 29 hours. Blastomere number, sister chromatid exchange (SCE), micronuclei, and chromosomal aberrations were observed. Morphologically, any protein supplement was better than no media supplement. Whole HCS and large-molecular-weight fraction provided the best conditions for embryo growth. Blastomere number was increased with whole serum when compared with no supplementation, small-molecular-weight fraction, or human serum albumin. In the analysis of SCE, all supplements had a lower SCE number than no serum supplement, and HCS supplement demonstrated a significantly lower SCE number than the other supplements. No difference in micronuclei or chromosomal aberration was observed in any of the supplements. In conclusion, whole HCS provides optimal conditions for culturing embryos, compared with the various serum fractions, and the beneficial components are primarily found in the large-molecular-weight fraction.