The effect of serum fractions on single-cell mouse embryos in vitro.

To examine the effect of various fractions of human fetal cord serum (HCS) on mouse embryos cultured in vitro, heat-inactivated HCS was separated by ultrafiltration into five distinct fractions: Fractions A, MW greater than 30,000; B, MW 30,000-10,000; C, MW 10,000-5,000; D, MW 5,000-1,000; and E, MW less than 1,000. Seven hundred twenty-eight single-cell embryos were cultured in TYH-280 medium supplemented with 8 mg/ml bovine serum albumin (BSA) and a 20% concentration of Fraction A, B, C, D, or E, whole HCS, or BSA alone. Embryos cultured with Fraction A or E or whole HCS demonstrated a significantly reduced growth rate (P less than 0.01), while embryos cultured with Fraction D demonstrated a significantly increased growth rate (P less than 0.01). Additionally, 649 single-cell embryos were cultured in medium which was supplemented with 8 mg BSA/ml and a 0, 1, 2, or 5% concentration of Fraction A or E. Fraction E displayed toxicity even at a 1% concentration (P less than 0.01), while Fraction A demonstrated growth inhibition at a 5% concentration (P less than 0.05) but increased the hatching rate at a 1% concentration (P less than 0.01). Finally, 635 single-cell embryos were cultured with four distinct fractions of HCS obtained from a Sephacryl S-200 column: Fractions I, MW 100,000; II, MW 70,000-100,000; III, MW 30,000-70,000; and IV, low molecular weight (less than 5,000).(ABSTRACT TRUNCATED AT 250 WORDS)