Abstract: Objective To investigate the effect of estradiol valerate (E₂V) on endometrial receptivity induced by clomiphene in polycystic ovary syndrome (PCOS) rats. Methods Rats were divided into control group (administered 0.9% sodium chloride solution), and PCOS model group (administered 50 mg/kg clomiphene), E₂V low, medium and high-dose intervention group [administered (0.2, 0.5, 1.0)mg/kg E₂V+50 mg/kg clomiphene]. Serum sex hormone level was compared. Morphological change of endometrium was examined by ELISA. The expression of estrogen receptor (ER), progesterone receptor (PR), homeobox gene (Hox)A10, empty ventilator homeobox (Emx)2, integrin α_vβ₃ mRNA and protein in the endometrium were detected by real-time fluorescence quantitative polymerase chain reaction (RT-qPCR) and Western blot. Results Compared with the control group, luteinizing hormone/follicle-forming hormone (LH/FSH), testosterone (T), relative expressions of Emx2 mRNA and protein were significantly increased (P＜0.05), while estradiol (E2) level, glandular area, glandular area, endometrial thickness and glandular/interstitial area ratio, relative expressions of ER, PR, HoxA10, integrin α_vβ₃ mRNA and protein were significantly decreased (P＜0.05). Compared with PCOS model group, the changes of above indexes in E₂V low, medium and high-dose intervention group were opposite (P＜0.05). Conclusions E₂V can improve endometrial receptivity of PCOS clomiphene-induced ovulation rats. E₂V is potentially related to the up-regulation of ER, PR, HoxA10, integrinα_vβ₃ and down-regulation of Emx2.

Key words: estradiol valerate, polycystic ovary syndrome, endometrial receptivity