Abstract: Abstract: Objective　To study the relationship between estrogen (E2) and progesterone (P) levels and Th17/Treg subgroups in the hemorrhagic model mice after medical abortion. Methods　Thirty-two female Balb/c mice with clean grade were selected and divided into normal pregnancy group (group A), low-dose mifepristone group (group B), high-dose mifepristone group (group C) and mifepristone + gongqing granules group (group D) by random number table method, with 8 mice in each group. Mice in group B, C and D were gavaged with mifepristone 0.88 mg·kg-1·d-1, 1.5 mg·kg-1·d-1 and mifepristone (1.5 mg·kg-1·d-1) + gongqinggranules (308.16 mg·kg-1·d-1) during d 6 pregnancy, respectively. Alkaline hematin photometric method was used to detect uterine blood loss. The serum E2 and P levels were detected by rdioimmunoassay (RIA). The uterus tissue Th17 (CD3+CD4+IL-17A+), Treg (CD4+CD25+Foxp3+) and the ratio of Th17/Treg subsets were detected by flow cytometry double staining method, and the uterus tissue interleukin 17A (IL-17A), interleukin 10 (IL-10) and transforming growth factor (TGF-β) mRNA levels were detected by RT-PCR method. Results　The uterine bleeding volume decreased in turn in group B, group C and group D (P＜0.05). After drug abortion, the E2 levels increased in turn in group A, group B, group C and group D, while the P levels decreased in turn in group A, group B, group C and group D (P＜0.05). The ratio of Th17 and Th17/Treg subgroups of mice decreased in turn in the four groups, while the Treg subgroup ratio decreased in turn (P＜0.05). The levels of IL-17A mRNA increased in turn in the four groups (P＜0.05), and the levels of IL-10 mRNA and TGF- β mRNA were decreased in turn in the four groups (P＜0.05). The serum level of E2 was positively correlated with Th17, Th17/Treg and IL-17A mRNA, and negatively correlated with Treg, IL-10 and TGF-β (all P＜0.05). The serum level of P was positively correlated with Treg, IL-10 and TGF-β, and negatively correlated with Th17, Th17/Treg and IL-17A (all P＜0.05). Conclusion　The changes of serum E2 and P levels in abnormal uterine bleeding after medical abortion are closely related to the changes of Th17/Treg subgroup ratio, and inducing Th17/Treg subgroup to migrate to Th17 can help reduce uterine bleeding.

Key words: abortion, induced, uterine hemorrhage, estradiol, progesterone, Th17 cells, T-lymphocytes, regulatory