Decreased expression of endometrial vessel AQP1 and endometrial epithelium AQP2 related to anovulatory uterine bleeding in premenopausal women.
OBJECTIVE
Aquaporins (AQPs) may be involved in the occurrence of abnormal uterine bleeding as the mediators between ovarian steroids and cyclic endometrial changes. The aim of the present study was to investigate the characteristics of endometrial AQPs in women with anovulatory uterine bleeding and explore the relationship between endometrial AQPs and ovarian steroids.


METHODS
Sixty-one women with premenopausal anovulatory uterine bleeding and 108 women with normal cycles were involved in this study. Endometrial biopsies were obtained from the women with anovulatory uterine bleeding and normal control women. Serum estradiol and progesterone concentrations were measured with enzyme-linked immunosorbent assay on the same day as an endometrial biopsy was performed. AQP1 and AQP2 mRNA expression was evaluated using reverse-transcriptase polymerase chain reaction. Immunohistochemistry was used to localize AQP1 and AQP2 in the endometrium, and their expression was quantified by an image analysis/measuring system.


RESULTS
AQP1 was located in the endothelium of small vessels, whereas AQP2 was mainly found in luminal and glandular epithelium. The expression levels of AQP1 and AQP2 mRNA and protein were higher in the secretory phase than those in the proliferative phase (P < 0.01) in normal endometrium, and their expression was related to serum steroid hormones (P < 0.01). However, the expression of AQP1 and AQP2 decreased in the endometrium in anovulatory uterine bleeding comparing with normal endometrium (P < 0.01). The correlation between AQP expression and ovarian steroids vanished (P > 0.05) in anovulatory uterine bleeding.


CONCLUSIONS
Our findings indicate that cyclic expression of endometrial AQP1/AQP2 correlated with steroid hormone levels may be essential to normal endometrial function and decreased AQP1/AQP2 expression in endometrial vessels or epithelium may be involved in the occurrence of anovulatory uterine bleeding.
Feng
Chun
C
Department of Reproductive Endocrinology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.
Sun
Chao-Chao
CC
Wang
Ting-Ting
TT
He
Rong-Huan
RH
Sheng
Jian-Zhong
JZ
Huang
He-Feng
HF
D000328:Adult; D051398:Aquaporin 1 / Q000378:metabolism*; D051399:Aquaporin 2 / Q000378:metabolism*; D004717:Endometrium / Q000098:blood supply*; D004730:Endothelium, Vascular / Q000378:metabolism*; D004848:Epithelium / Q000378:metabolism; D004958:Estradiol / Q000097:blood; D005260:Female; D005498:Follicular Phase / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D008183:Luteal Phase / Q000378:metabolism; D017697:Premenopause; D011374:Progesterone / Q000097:blood; D014592:Uterine Hemorrhage / Q000378:metabolism*
D051399:Aquaporin 2; D051398:Aquaporin 1; D011374:Progesterone; D004958:Estradiol