Abstract: Objective To investigate the efficacy of Bushen Huoxue Fang (BSHXF, a traditional Chinese medicine formula) for improving recurrent spontaneous abortion (RSA) in mice and the role of tyrosine kinase (JAK2) and transcriptional activator (STAT3) signaling pathway in its therapeutic mechanism. Methods Female CBA/J mice were caged with male DBA/2 mice to establish RSA mouse models, which were randomly divided into model group, dydrogesterone group and BSHXF group, with the female mice caged with male BALB/c mice as the control group (n=6). From the first day of pregnancy, the mice were subjected to daily intragastric administration of BSHXF, dydrogesterone, or distilled water (in control and model groups) for 12 days. After the treatments, serum levels of antithrombin III (AT-III), activated protein C (APC), tissue plasminogen activator (t-PA), progesterone, human chorionic gonadotropin (HCG), and estradiol (E2) were detected in each group using ELISA. HE staining was used to observe the morphological changes of the endometrium of the mice. Western blotting was performed to determine the expressions of p-JAK2, p-Stat3 and Bcl-2 in the placenta of the mice. Results Compared with the control mice, the mouse models of RSA showed a significantly increased embryo loss rate with decreased serum levels of AT- III, T- PA, progesterone, APC and HCG, increased placental expressions of p-JAK2, p-STAT3 and Bax, and decreased expression of Bcl-2 (P<0.05). Treatments with BSHXF and dydrogesterone both increased serum levels of AT-III, t-PA and HCG in the mouse models; Serum APC level was significantly reduced in BSHXF group and serum progesterone level was significantly increased in dydrogesterone group (P<0.05). Conclusion BSHXF can improve the prethrombotic state and inhibit cell apoptosis by downregulating the JAK2/STAT3 pathway to increase the pregnancy rate in mouse models of RSA.

Key words: JAK2/STAT3; recurrent spontaneous abortion; Bushen Huoxue Fang; prethrombotic state