Abstract: Objective To explore the effect of Panax notoginseng saponins on uterine bleeding in aborted rats and its possible mechanism. Methods Ten non-pregnant female rats were taken as the blank control group. Female rats conceived on the same day were induced with mifepristone (8.3 mg/kg) and misoprostol (100 μg/kg) to establish abnormal uterine bleeding ( AUB) model, and were divided into the model group, the positive group (Duanxueliu tablets, 0.45 g/kg), the Panax notoginseng saponins low- (25 mg/kg), medium- (50 mg/kg), high- ( 100 mg/kg) dose groups, with 10 rats in each group. The positive group and the Panax notoginseng saponins groups were given corresponding doses of drugs by gavage, once a day, for 7 days. Ultraviolet spectrophotometry was used to measure the amount of uterine bleeding in rats. Enzyme-linked immunosorbent assay (ELISA) was used to detect the levels of plasma tumor necrosis factor-α (TNF-α), interleukin-6 (IL- 6), estradiol (E2), progesterone (P) and 6-ketoprostaglandin F1α (6-keto-PGF1α) and thromboxane B2 (TXB2). HE and Masson staining methods were used to observe the pathological damage of the endometrium. Immunofluorescence staining was used to detect microvessel density (MVD) in endometrial tissue. Real-time fluorescent quantitative PCR (qPCR) was used to detect the expression of vascular endothelial growth factor (VEGF), matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) mRNA in uterine tissue. Results Compared with the blank control group, the plasma 6- keto-PGF1α, TNF- α, IL-6 levels, endometrial fibrosis area ratio, MMP-2 and MMP-9 mRNA expression levels were significantly higher in the model group, while the TXB2, E2, P levels, endometrial thickness, number of glands, endometrial MVD, and VEGF mRNA expression were significantly lower (P＜0.05). Compared with the model group, the amount of uterine bleeding, the plasma 6-keto-PGF1α, TNF- α, IL-6 levels, endometrial fibrosis area ratio, MMP-2 and MMP-9 mRNA expression levels were significantly lower in the Panax notoginseng saponins high-dose groups, while the TXB2, E2 levels, endometrial thickness, number of glands, endometrial MVD, and VEGF mRNA expression levels were significantly higher (P＜0.05). Conclusion Panax notoginseng saponins can treat uterine bleeding in aborted rats, and its mechanism of action may be related to inhibiting excessive fibrosis and inflammation, up-regulating the expression of VEGF, promoting vascular remodeling, and promoting endometrial repair

Key words: SANCHINOSIDE, abortion, incomplete, uterine hemorrhage, endometrium, inflammation, vascular remodeling, Panax notoginseng saponins