Geburtshilfe Frauenheilkd 2016; 76 - P208
DOI: 10.1055/s-0036-1592757

The serum protein fetuin-b increases in vitro fertilization rate in mice by inhibiting premature zona pellucida hardening

E Dietzel 1, J Floehr 1, E Van de Leur 2, R Weiskirchen 2, W Jahnen-Dechent 1
  • 1Universitätsklinikum der RWTH Aachen, Zell- und Molekularbiologie an Grenzflächen, Aachen, Deutschland
  • 2Universitätsklinikum der RWTH Aachen, Institut für Molekulare Pathobiochemie, Experimentelle Gentherapie und Klinische Chemie, Aachen, Deutschland

Objective: To prevent premature zona pellucida hardening (ZPH) by fetuin-B supplementation and thus to increase in vitro fertilization (IVF) rate.

Materials: recombinant mouse fetuin-B, rmFetuB; metaphase 2 stage oocytes and freshly isolated sperm from C57BL/6 mice.

Methods: We fertilized batches of 20 – 30 mouse oocytes in vitro and studied early embryo development until blastocyst hatching. Oocytes were kept with or without rmFetuB during in vitro culture (IVC) and IVF. ZPH was judged by chymotrypsin digestion and by counting the number of attached sperm.

Results: In the absence of cumulus cells, rmFetuB dose-dependently inhibited ZPH (p = 0.0002) and increased IVF rate (p = 0.039). Fetuin-B at 0.03 mg/ml and over also inhibited physiological, fertilization-triggered ZPH. Supplementation of culture medium with rmFetuB increased IVF rate for up to five hours of IVC.

Fig. 1: Fetuin-B

Summary: In vivo fetuin-B inhibits ovastacin and thus ZPH until after fertilization. In vitro fetuin-B concentration decreases after oocyte isolation leading to spontaneous ZPH which blocks fertilization. Supplementation of oocyte IVC media with rmFetuB increased fertilization rate, and did not negatively affect further embryo development.