Oenothera biennis improves pregnancy outcomes by suppressing inflammation and fibrosis in an intra-uterine adhesion rat model

Intrauterine adhesion (IUA), also referred to as Asherman's syndrome, is characterized by fibrosis, inflammation, and can cause amenorrhea and infertility due to abnormal endometrial healing. Histological and Molecular methods were used to evaluate the efficacy of EPO, which is traditionally known for its anti-inflammatory and fibrinolytic properties, in preventing the formation of IUA. Oral administration of EPO reduced the formation of adhesion bands and promoted endometrial regeneration. EPO administration decreased extracellular matrix accumulation, evidenced by the down-regulation of tissue COL1A1 and COL3A1 expression. The anti-inflammatory effect of EPO was confirmed by a reduction in oxidants and down-regulation of pro-inflammatory cytokines including TNF-α, IL-6, IFN-γ, and IL-1β. Furthermore, EPO improved embryonic development parameters, including size and weight of embryo, as well as increased embryo count and live embryo percentage in the rat IUA model. EPO also positively enhanced implantation markers, particularly enlargement and mass gain in the placenta of the treated group, consequently improving pregnancy outcomes such as the number of babies, percent of live babies, baby weight and gestation time. Histopathological investigation provides evidence that oral administration of EPO showed no toxicity on the main three organs including liver, kidney and heart. These results showed that EPO can be considered as a safe and natural product with potent anti-inflammatory and fibrinolytic properties without any observed side effects for the treatment of IUA.