Amphiregulin stimulates cumulus-oocyte expansion and oocyte maturation in rhesus macaques

PELUFFO, MC; STOUFFER, RL; ZELINSKI, MB; HENNEBOLD, JD

Denver, Colorado

Congreso; 66th ASRM Annual Meeting; 2010

ASRM (American Society of Reproductive Medicine)

Objective: To determine the role of the epidermal growth factor (EGF) family member, amphiregulin (AREG), on rhesus macaque cumulus-oocyte expansion (C-OE) and oocyte maturation. Design: In vitro study using cumulus-oocyte complexes (COCs) obtained from rhesus macaques. Materials and Methods: COCs (n= 55) were incubated for 30 h in TALP media under the following conditions: media with monkey serum (MS, control) alone or with AREG (10 ng/ml or 50 ng/ml). A fluorescence-based technique was used to evaluate extracellular levels of hyaluronic acid (HA) in treated COCs, as its synthesis is critical for C-OE. COCs from healthy small antral follicles were isolated from the macaque ovarian medulla after collagenase treatment. Individual COCs (n=90) were cultured for 48 h with MS and gonadotropins alone or with AREG (10 ng/ml or 100 ng/ml). At 48h, germinal vesicle (GV) breakdown (metaphase I, MI), the presence of a polar body (metaphase II, MII), and spindle assembly was determined by microscopy. Results: AREG treatment of rhesus macaque COCs induced HA levels in the matrix that surrounds the cumulus cells. In the absence of AREG, however, COC HA staining was minimal. AREG (10 ng/ml) incubation with rhesus macaque COCs increased the percentage of oocytes that progressed to the MII stage of meiosis relative to the control group (82% vs. 33%, p<0.05), as well as decreased the percentage of MI oocytes (6% vs. 39%, p<0.05). Surprisingly, the percentage of either MI or MII oocytes was not different between the 100 ng/ml AREG group and controls. Conclusions: These data indicate, for the first time in primates, that AREG may play a role in C-OE as well as in oocyte nuclear maturation at a specific concentration. Thus, further studies are warranted to determine if AREG can serve as an intrafollicular marker of C-OE and oocyte competence in primates. Support: Oncofertility Consortium NIH 1 UL1 RR024926 (R01 HD058294, PL1 EB008542), RR00163, U54 HD55744 and a Lalor Foundation Postdoctoral Fellowship (MCP).