In view of ovarian steroidogenesis and luteal construction to explore the effects of Bushen Huoxue recipe in mice of ovarian hyperstimulation

ETHNOPHARMACOLOGICAL RELEVANCE

Bushen Huoxue recipe (BSHXR) is a widely used prescription medicine for treating gynecological diseases. We have previously found that BSHXR can improve the pregnancy outcome of controlled ovarian hyperstimulation (COH) mice by modulating the abnormal high level of progesterone. While the pharmacological mechanism of such therapeutic effect is not clear.

AIM OF THE STUDY

We aimed to investigate the effects of BSHXR on the ovarian steroidogenesis and luteal function in mice undergoing COH.

MATERIALS AND METHODS

A COH mouse model was established via an intraperitoneal injection of 0.4 IU/g pregnant mare serum gonadotropin (PMSG) and 1 IU/g human chorionic gonadotropin (HCG). The histological features of ovaries were observed using hematoxylin-eosin staining. The expression levels of FSHR, LHCGR, and key molecules in ovarian steroidogenesis, including CYP11A1, CYP17A1, CYP19A1, HSD3B1, and StAR, were examined via immunohistochemical staining, western blotting, and RT-qPCR. CD31, VEGFA, and FGF2 levels were assessed to evaluate ovarian vascularization. The protein and mRNA levels of ovarian ERK1/2, p-ERK1/2, MEK1/2, and p-MEK1/2 were also detected using western blotting, RT-qPCR, or immunofluorescence staining.

RESULTS

COH mice had a significantly increased volume and weight of the ovary and number of corpora lutea. In particular, COH exhibited a long-term influence on ovarian FSHR and LHCGR expression, disrupting the levels of CYP11A1, HSD3B1, and CYP17A1, causing poorer luteal angiogenesis. Compared with normal mice, the expression levels of ovarian VEGFA and FGF2 in COH mice were considerably lower on Day 1 after PMSG. On concomitant HCG treatment, both VEGFA and FGF2 expression surged dramatically on ED1 and then declined on ED4 and ED8. Moreover, the expression pattern of MEK1/2-ERK1/2 was almost consistent with that of VEGFA and FGF2. After treatment, BSHXR increased ovarian LHCGR, FSHR, CYP11A1, HSD3B1, and CYP17A1 levels, boosted luteal vascularization, and restored MEK1/2-ERK1/2 signaling in COH mice.

CONCLUSION

BSHXR restored the abnormally high progesterone level by regulating the CYP11A1 and HSD3B1 expression as well as promoted luteal angiogenesis, which was related with LHCGR-MEK1/2-ERK1/2-VEGFA/FGF2 signaling pathway in the ovary. This effect prevented the fluctuation of sex hormones in COH mice and benefited the outcome of pregnancy.