Abstract: Objective:Yun Kang oral liquid is a listed proprietary Chinese Medicine. To further evaluate its efficacy, this experiment established a kidney deficiency and luteum inhibition threatened abortion rat model to observe the effects of Yun Kang oral liquid. Methods: Sixty pregnant rats were randomly divided into normal control group (NC), model group (MG), dydrogesterone group (DT, 3.02 mg/kg), and Yun Kang oral liquid low-dose group (YK-L, 4 ml/kg), medium dose group (YK-M, 6 ml/kg), high dose group (YK-H, 9 ml/kg), 10 in each group. On the first day of pregnancy, each administration group was treated with the test drug at the prescribed dose every morning, and the NC group and the MG group were given an equal volume of purified water for 10 days; the rats were intragastrically administrated every afternoon, except for the NC group. In addition, the other groups were intragastrically administered with hydroxyurea at a dose of 450 mg/kg for 9 days, and mifepristone was administered at a dose of 4.0 mg/kg on the 10th day. On the 9th day of pregnancy, behavioral signs such as back temperature, grasping force, pain threshold, and autonomic activity were measured in each group. On the 11th day of pregnancy, blood was collected from the abdominal aorta in each group to determine serum levels of estradiol (E₂) , progesterone (P) and thromboxane B₂ (TXB₂) . Ovary and fetal uterus were removed, the number and diameter of embryos were observed, and the ovary and uterus indexes were calculated. Results: Compared with the NC group, the back temperature, grip, pain threshold, number of spontaneous activities, number of embryos, embryo diameter, uterus index and serum E₂, P, TXB₂ levels in the MG group were decreased significantly (P＜0.05, 0.01). Compared with the MG group, the back temperature, grasping force, number of embryos, embryo diameter and serum E₂ and P levels were increased significantly in each dose group (P＜0.05, 0.01); the pain threshold, autonomic activity, and uterus index of YK-M and YK-H group were increased significantly (P＜0.05); serum level of TXB₂ in YK-H group were increased significantly (P＜0.05). Conclusion: Yun Kang oral liquid has a clear kidney-filling effect on rats with threatened abortion caused by kidney deficiency-luteal suppression. The mechanism may be related to raising serum E₂, P, TXB₂ levels, improving kidney deficiency and improving embryo quality.

Key words: Yun Kang oral liquid, kidney deficiency, luteum inhibition, threatened abortion, rats