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Link protein as an enhancer of cumulus cell–oocyte complex expansion
Author(s) -
Sun Guang Wei,
Kobayashi Hiroshi,
Suzuki Mika,
Kanayama Naohiro,
Terao Toshihiko
Publication year - 2002
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/mrd.90008
Subject(s) - cumulus oophorus , oocyte , biology , polyclonal antibodies , alpha (finance) , medicine , endocrinology , microbiology and biotechnology , andrology , ovarian follicle , antibody , ovary , immunology , embryo , construct validity , nursing , patient satisfaction
To investigate the specific components involved in regulating cumulus cell–oocyte complex (COC) expansion in an in vitro mouse experiment, freshly‐isolated COC were cultured in the presence of various combinations of FSH (1.0 μg/ml), proteins of the inter‐α‐inhibitor (IαI) family (a light chain, also known as bikunin, heavy chains [HC1 + HC2] and IαI [0.01–2.0 μg/ml]) and link protein (LP) (0.016–10 μg/ml) for 24 h and were observed for expansion of their cumulus cells (percent of COC with + 3 and + 4 expansion and average projected area). The COC were videotaped in real time at the initiation of culture and after 24 h of culture. FSH alone did not stimulate cumulus expansion under serum‐free conditions; however, treatment with IαI (0.1–2.0 μg/ml) or heavy chains (10 μg/ml), but not bikunin (10 μg/ml), in the presence of FSH significantly increased COC expansion, with maximal promotion occurring at 1.0 μg/ ml of IαI. Addition of LP (2.0 μg/ml) to the medium containing IαI (1.0 μg/ml) and FSH resulted in significantly higher expansion levels than were observed in response to IαI alone, although LP alone (10 μg/ml) had no or very little effect by itself. Anti‐IαI or anti‐LP polyclonal antibody, which inhibits binding of IαI and LP, respectively, to hyaluronic acid (HA), markedly reduced expansion of the surrounding cumulus cell extracellular matrices. Therefore, in vitro, LP might serve, in part, to enhance the COC expansion possibly by stabilizing HA‐IαI (or heavy chains) complex on the surrounding cumulus cell matrices. Mol. Reprod. Dev. 63: 223–231, © 2002 Wiley‐Liss, Inc.