Reduced expression and function of aquaporin-3 in mouse metaphase-II oocytes induced by controlled ovarian hyperstimulation were associated with subsequent low fertilization rate.
OBJECTIVE
Aquaporin-3 (AQP3), one isoform of water channel family, has been found to be expressed in mouse oocytes. The present study aimed to investigate whether functional AQP3 was expressed in oocytes induced by controlled ovarian hyperstimulation (COH), and whether altered oocyte AQP3 expression was associated with changes in fertilization rate.


METHODS
Sixty ICR female mice were divided into two groups: COH and control. AQP3 mRNA expression of mouse metaphase II (MII) oocytes was quantified by real-time RT-PCR. The water permeability of oocytes was assessed with cell swelling test. The fertilization profiles of oocytes were generated via in vitro fertilization.


RESULTS
AQP3 mRNA was expressed in both natural and COH-induced mouse oocytes. COH significantly reduced AQP3 mRNA expression. The volume of oocytes was significantly increased after exposure to hypotonic medium and pretreatment with HgCl(2) attenuated hypotonic medium-induced increase in oocyte volume and water permeability coefficient (Pf). Furthermore, the expression of AQP3, Pf and the fertilization rate were significantly lower in COH oocytes than those in control.


CONCLUSIONS
AQP3 might play an important role in controlling oocyte quality and a low in vitro fertilization rate of COH mice might, in part, result from reduced AQP3 expression and water permeability in mouse oocytes.
Meng
Qing-Xia
QX
Department of Reproductive Endocrinology, Women's Hospital, School of Medicine, Zhejiang University, Zhejiang, China.
Gao
Hui-Juan
HJ
Xu
Chen-Ming
CM
Dong
Min-Yue
MY
Sheng
Xia
X
Sheng
Jian-Zhong
JZ
Huang
He-Feng
HF
D000818:Animals; D051400:Aquaporin 3 / Q000235:genetics* / Q000378:metabolism*; D005260:Female; D005306:Fertilization / Q000502:physiology*; D005786:Gene Expression Regulation; D008297:Male; D008677:Metaphase; D051379:Mice; D008813:Mice, Inbred ICR; D009865:Oocytes / Q000166:cytology* / Q000378:metabolism*; D010062:Ovulation Induction; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
D012333:RNA, Messenger; D051400:Aquaporin 3