Expression of interleukin-18 and its receptor in mouse ovary.
OBJECTIVE
Interleukin-18 (IL-18) strongly induces interferon-gamma production and is produced not only by types of immune cells but also by types of non-immune cells. Ovulation is thought to be an inflammation-like reaction in which many pro-inflammatory cytokines are involved. We investigated whether IL-18 is involved in the functions of ovary.


METHODS
The 4-week-old immature female mice were examined for IL-18 and IL-18 receptor (IL-18R) expression on their ovaries under stimulation with pregnant mare's serum gonadotropin (PMSG) and human chorionic gonadotropin (hCG) by immunohistochemical staining, Western blotting and reverse transcript-polymerase chain reaction. The IL-18R was blocked by the injection of anti-IL-18R monoclonal antibody to immature mice during PMSG-hCG stimulation, and the number of ovulated ova was counted.


RESULTS
The expression of both proteins and mRNA of IL-18 and IL-18R were very low in immature ovaries before stimulation, but after PMSG injection both IL-18 and IL-18R increased dramatically in theca cells and reached a maximum level at the peri-ovulatory phase then slightly lowered, but still kept a high level during the luteal phase in the corpus luteum. The treatment of IL-18R monoclonal antibody to the mice during ovarian stimulation reduced the number of ovulated ova and inhibited the expansion of cumulus cells surrounding the ovum.


CONCLUSIONS
IL-18 and IL-18R play roles in various kinds of function of ovary.
Tsuji
Y
Y
Department of Obstetrics and Gynecology, Hyogo College of Medicine, Japan. yoshi416@hyo-med.ac.jp
Tamaoki
T H
TH
Hasegawa
A
A
Kashiwamura
S
S
Iemoto
A
A
Ueda
H
H
Muranaka
J
J
Adachi
S
S
Furuyama
J
J
Okamura
H
H
Koyama
K
K
D000818:Animals; D015153:Blotting, Western; D006063:Chorionic Gonadotropin / Q000494:pharmacology; D005260:Female; D006064:Gonadotropins, Equine / Q000494:pharmacology; D007150:Immunohistochemistry; D020382:Interleukin-18 / Q000032:analysis* / Q000235:genetics / Q000502:physiology; D053727:Interleukin-18 Receptor alpha Subunit; D051379:Mice; D008813:Mice, Inbred ICR; D008970:Molecular Weight; D010053:Ovary / Q000737:chemistry*; D010060:Ovulation; D018123:Receptors, Interleukin / Q000032:analysis* / Q000235:genetics / Q000502:physiology; D053724:Receptors, Interleukin-18; D020133:Reverse Transcriptase Polymerase Chain Reaction
D006063:Chorionic Gonadotropin; D006064:Gonadotropins, Equine; C508572:IL18R1 protein, human; C508573:Il18r1 protein, mouse; D020382:Interleukin-18; D053727:Interleukin-18 Receptor alpha Subunit; D018123:Receptors, Interleukin; D053724:Receptors, Interleukin-18