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Comment |
[P2-252] Involvement of Complement System in the Ovulation.
Giyoun Na, Mary C Gieske, CheMyong Ko, Yongbum Koo. Sch of Biotechnology and Biomed Sci, Inje Univ, Gimhae, Republic of Korea; Clin Scis, Univ of Kentucky, Lexington, KY
It is well known that the ovulation is an inflammatory-like process, which may involve the activation of complement system. Complement system is composed of various proteins that are sequentially activated by inflammatory signal resulting in the formation of membrane attack complex (MAC), which disrupts various types of cell membranes. At the site of inflammatory reaction, on the other hand, host cells produce regulators of complement systems which inhibit the MAC formation. In order to see whether complement system is involved in the ovulatory process, expression patterns of the membrane bound forms of regulators of complement activation (RCA) were examined in the periovulatory stage ovaries. For this purpose, a rat ovarian gene expression database (rOGED) was used. rOGED provides quantitative temporal mRNA expression profiles of 31,000 genes at ovarian (OVA), granulosa cell (GC), and non-granulosa/oocyte ovarian tissue (NGO) levels at various stages of follicular development (Abstract #852214). Of the three main types of RCAs, rOGED detected the expressions of mRNAs for membrane inhibitor of reactive lysis (CD59) and decay accelerating factor (DAF; CD55), but not membrane co-factor protein (MCP). CD59 mRNA was expressed both in GC and NGO all over the time points examined, with the peak expression at 12 h post treatment hCG. Expression of DAF mRNA was dramatically, yet transiently increased at 6 h post hCG treatment. Ten fold higher expression of DAF mRNA was detected in NGO than in GC at all time points examined. Northern blot analyses have confirmed the tissue- and time-dependent expression patterns of the rOGED data. We further examined the expression patterns of the various components of complement system. Surprisingly, within 6 hours of hCG treatment, two fold increase in mRNA expression was observed in the mRNAs for C1q , C3 and C4 proteins. Interestingly, those components were detected only in the NGO, except C1 that is expressed both in GC and NGO. The ovulatory inflammatory reaction is known to facilitate the process of follicle rupture. The inflammatory reaction, however, may give serious damages to the growing follicles, ovulated follicles and other important ovarian tissues. Present study strongly indicates that complement system may be involved in the ovulatory inflammation and the RCAs are expressed to protect ruptured follicles as well as other parts of the ovarian tissues from the potential attack by the complement system.
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