Soluble Fas concentrations in the follicular fluid and oocyte-cumulus complex culture medium from women undergoing in vitro fertilization: association with oocyte maturity, fertilization, and embryo quality.

OBJECTIVE

Because soluble Fas (sFas) inhibits Fas-mediated apoptosis by preventing death signal transduction, we determined sFas concentrations in the follicular fluid (FF) and oocyte-cumulus complex culture medium (CM) from women undergoing in vitro fertilization (IVF) in order to associate its concentrations with oocyte maturity, fertilization, and embryo quality.

METHODS

We studied 82 follicles from 11 healthy women (mean age, 35.4 +/- 3.8 years) using a long protocol for IVF treatment. Individual FF and matched CM samples were immediately centrifuged at 4C and sFas concentrations were determined by sandwich enzyme-linked immunosorbent assays.

RESULTS

sFas concentrations were significantly higher in FF than in CM (P <.0001) and when oocytes were mature rather than immature (P <.002). Of 70 mature and 12 immature oocytes, 56 (80%) and two (16.6%), respectively, were fertilized. sFas concentrations in CM were significantly lower when mature oocytes were fertilized versus nonfertilized (P <.005). sFas concentrations in FF and CM were significantly related in an inverse manner to embryo quality (P = .004 and P = .0002, respectively).

CONCLUSION

FF and CM from women undergoing IVF contain sFas. The latter has anti-apoptotic properties and levels are higher: in FF when oocytes are mature and in CM when oocytes are nonfertilized. Furthermore, FF and CM sFas concentrations are negatively correlated with embryo quality.