ABSTRACT
PURPOSE: Our purpose was to determine the effect of Synthetic Serum Substitute (SSS) versus serum supplementation on fertilization rates and subsequent development of embryos from patients undergoing IVF. PROCEDURE: Experiment I compared the effects of SSS to human serum on mouse embryo development. Two hundred one-cell B6D2F1 mouse embryos were cultured in 100-microliter droplets of human tubal fluid (HTF) containing either (1) no protein (control; n = 37), (2) 15% serum from women with tubal infertility (n = 44), (3) 15% serum from women with endometriosis (n = 49), (4) 15% fertile donor serum (n = 33), or (5) 15% SSS (n = 37). Experiment II compared the effects of SSS to human serum on the development of embryos from patients undergoing IVF. Thirty-three women were included in this study. A total of 371 oocytes was cultured in HTF containing either (1) maternal or donor serum (n = 140) or (2) 15% SSS (n = 231). Embryo development was evaluated 48 hr after fertilization. RESULTS: In Experiment I, the rate of blastocyst development was evaluated at 48, 72, and 96 hr of culture. Sixty-four and nine-tenths percent of embryos cultured in SSS were morulae at 48 hr of culture (versus 5.4, 0, 8.2, and 6.1 in Groups 1, 2, 3, and 4, respectively). By 72 hr, 29.7% of these embryos had developed into blastocysts (versus 0, 0, 8.2, and 3.0, for Groups 1, 2, 3, and 4, respectively). This percentage increased to a total of 83.7 after 96 hr (versus 27.0, 20.4, 38.8, and 39.4 for Groups 1, 2, 3, and 4, respectively). Forty-three and two-tenths percent of the blastocysts cultured in SSS had hatched from their zonae by 96 hr. With the exception of Group 5, which had a rate of 9.1%, embryo hatching was not observed in any of the groups at the termination of culture (96 hr). In Experiment II there were no differences in cell stage or quality of human embryos cultured in SSS or serum, but fertilization rates tended to be better (P = 0.07) for oocytes inseminated in media containing SSS (70.0%, vs 55.0% for serum). CONCLUSIONS: SSS appears to be a superior protein source for mouse embryo growth and is as good as serum from fertile donors in promoting in vitro human embryo development.
