The Th1/Th2/Th17/Treg paradigm induced by stachydrine hydrochloride reduces uterine bleeding in RU486-induced abortion mice.

ABSTRACT

ETHNOPHARMACOLOGICAL RELEVANCE The Th1/Th2/Th17/Treg paradigm plays an important role in achieving maternal-fetal immunotolerance and participates in RU486-induced abortion. Excessive uterine bleeding is the most common side effect of RU486-induced abortion; however, its etiopathogenesis has not been fully understood. Therefore, elucidating the correlation between the Th1/Th2/Th17/Treg paradigm and the volume of uterine bleeding may offer novel therapeutic target for reducing uterine bleeding in RU486-induced abortion. Leonurus sibiricus has been used in clinics to reduce postpartum hemorrhage with low toxicity and high efficiency; however, the effective constituents and therapeutic mechanism have not been described. Stachydrine hydrochloride is the main constituent of L. sibiricus, therefore L. sibiricus is regarded as a candidate for reducing uterine bleeding in RU486-induced abortion mice by regulating the Th1/Th2/Th17/Treg paradigm. AIM OF THE STUDY The purpose of this study was to determine the Th1/Th2/Th17/Treg paradigm in uterine bleeding of RU486-induced abortion mice and to elucidate the immunopharmacologic effects of stachydrine hydrochloride on inducing the Th1/Th2/Th17/Treg paradigm in reducing the uterine bleeding volume in RU486-induced abortion mice. MATERIALS AND METHODS: To investigate the Th1/Th2/Th17/Treg paradigm in uterine bleeding during RU486-induced abortion mice, pregnant BALB/c mice were treated with high- and low-dose RU486 (1.5mg/kg and 0.9 mg/kg, respectively), and the serum progesterone (P(4)) protein level, uterine bleeding volume, and proportions of Th1/Th2/Th17/Treg cells in mice at the maternal-fetal interface were detected by ELISA assay, alkaline hematin photometric assay, and flow cytometry, respectively. To determine the regulatory effect of stachydrine hydrochloride on the Th1/Th2/Th17/Treg paradigm in vitro, splenocytes of non-pregnant mice were separated and treated with P(4,) RU486, and/or stachydrine hydrochloride (10(-5)M, 10(-4)M, and 10(-3)M, respectively). The proportions of Th1/Th2/Th17/Treg cells were analyzed using flow cytometry. To evaluate the effect of stachydrine hydrochloride in reducing uterine bleeding via regulation of the Th1/Th2/Th17/Treg paradigm, pregnant mice were treated with RU486 (1.5mg/kg) and/or stachydrine hydrochloride (2.5mg/kg, 5mg/kg, and 10mg/kg). The serum P(4) level, uterine bleeding volume, and proportions of Th1/Th2/Th17/Treg cells at the mice maternal-fetal interface were detected. Moreover, the protein levels of cytokines (IL-12 and IL-6) and the cytokine soluble receptors were analyzed by ELISA assay, and the mRNA expression of transcription factors (T-bet, GATA-3, RORγt, and Foxp3) were detected by RT-PCR assay. RESULT: Th1- and Th17-biased immunity was observed in RU486-induced abortion mice. The volume of uterine bleeding during RU486-induced abortion was negatively related to the proportions of Th1 and Th17 cells, as well as the ratios of Th1Th2 cells and Th17Treg cells, and positively related to the proportions of Th2 and Treg cells. Stachydrine hydrochloride promoted the protein expression of IL-12 and IL-6, as well as the mRNA expression of T-bet and RORγt, while inhibiting the mRNA expression of GATA-3 and Foxp3. Therefore, the Th1/Th2/Th17/Treg paradigm in RU486-induced abortion mice shifted to Th1 and Th17 after stachydrine hydrochloride administration. The volume of uterine bleeding during RU486-induced abortion was reduced significantly after stachydrine hydrochloride administration. CONCLUSION: The Th1/Th2/Th17/Treg paradigm is closely related to the volume of uterine bleeding in RU486-induced abortion mice. The Th1/Th2/Th17/Treg paradigm induced by stachydrine hydrochloride contributed to the reduction in uterine bleeding in RU486-induced abortion mice.