title: Hormonal regulation of ovarian bursa fluid in mice and involvement of aquaporins.
abstract: In rodent species, the ovary and the end of oviduct are encapsulated by a thin membrane called ovarian bursa. The biological functions of ovarian bursa remain unexplored despite its structural arrangement in facilitating oocytes transport into oviduct. In the present study, we observed a rapid fluid accumulation and reabsorption within the ovarian bursa after ovarian stimulation (PMSG-primed hCG injection), suggesting that the ovarian bursa might play an active role in regulating local fluid homeostasis around the timing of ovulation. We hypothesized that the aquaporin proteins, which are specialized channels for water transport, might be involved in this process. By screening the expression of aquaporin family members (Aqp1-9) in the ovarian tissue and isolated ovarian bursa (0, 1, 2 and 5 h after hCG injection), we found that AQP2 and AQP5 mRNA showed dynamic changes after hCG treatment, showing upregulation at 1-2 h followed by gradually decrease at 5 h, which is closely related with the intra-bursa fluid dynamics. Further immunofluorescence examinations of AQP2 and AQP5 in the ovarian bursa revealed that AQP2 is specifically localized in the outer layer (peritoneal side) while AQP5 localized in the inner layer (ovarian side) of the bursa, such cell type specific and spatial-temporal expressions of AQP2 and 5 support our hypothesis that they might be involved in efficient water transport through ovarian bursa under ovulation related hormonal regulation. The physiological significance of aquaporin-mediated water transport in the context of ovarian bursa still awaits further clarification.
authors.affiliation: College of Veterinary Medicine, Northwest A & F University, Yangling, Shaanxi, China.
authors.forename: He
authors.initials: H
authors.lastname: Zhang
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang
authors.forename: Huashan
authors.initials: H
authors.lastname: Zhao
authors.forename: Yunfang
authors.initials: Y
authors.lastname: Zhang
authors.forename: Qi
authors.initials: Q
authors.lastname: Chen
authors.forename: Hongying
authors.initials: H
authors.lastname: Peng
authors.forename: Li
authors.initials: L
authors.lastname: Lei
authors.forename: Jingqiao
authors.initials: J
authors.lastname: Qiao
authors.forename: Junchao
authors.initials: J
authors.lastname: Shi
authors.forename: Zhonghong
authors.initials: Z
authors.lastname: Cao
authors.forename: Enkui
authors.initials: E
authors.lastname: Duan
authors.forename: Yaping
authors.initials: Y
authors.lastname: Jin
mesh_terms: D000818:Animals; D020346:Aquaporins / Q000235:genetics / Q000378:metabolism*; D001692:Biological Transport / Q000187:drug effects* / Q000235:genetics; D006063:Chorionic Gonadotropin / Q000008:administration & dosage*; D005260:Female; D006064:Gonadotropins, Equine / Q000008:administration & dosage*; D006706:Homeostasis / Q000187:drug effects / Q000235:genetics; D051379:Mice; D010053:Ovary / Q000187:drug effects* / Q000378:metabolism; D010060:Ovulation / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D010062:Ovulation Induction / Q000379:methods; D012333:RNA, Messenger / Q000235:genetics; D015854:Up-Regulation / Q000187:drug effects / Q000235:genetics; D014867:Water / Q000378:metabolism*
chemical_list: D020346:Aquaporins; D006063:Chorionic Gonadotropin; D006064:Gonadotropins, Equine; D012333:RNA, Messenger; D014867:Water