Zigui-Yichong-Fang protects against cyclophosphamide-induced premature ovarian insufficiency via the SIRT1/Foxo3a pathway

Abstract

Ethnopharmacological relevance: Zigui-Yichong-Fang (ZGYCF) is a traditional Chinese medicine prescription for the treatment of infertility and premature ovarian insufficiency (POI). It is clinically used to regulate hormone levels, improve ovarian reserve and increase pregnancy rate. However, the exact mechanism of action is not yet clear.

Aims of the study: This study aimed to explore the potential impact and mechanism of ZGYCF on POI, and provide a scientific basis for its clinical application.

Materials and methods: UHPLC‒MS/MS was used to identify the main compounds of ZGYCF. Female 8-week-old C57BL/6N mice were randomized into four group containing the vehicle control (Veh) group, the cyclophosphamide (CTX) model group, the low-dose ZGYCF (CTX-ZG-L) group and the high-dose ZGYCF (CTX-ZG-H) group. A mouse POI model was induced with a single intraperitoneal injection of CTX, and the therapeutic effects of different doses of ZGYCF on POI were evaluated according to the ovarian weight coefficient, serum AMH, serum E₂, ovarian histomorphology and follicle counts. After the dose screening experiment, the CTX-ZG-L group was renamed the CTX-ZG group and subjected to follow-up experiments. RNA-seq was used to explore the mechanism of POI and the therapeutic mechanism of ZGYCF on POI in Veh group, CTX group and CTX-ZG group. The mechanism of action of ZGYCF on POI were determined by measuring serum hormone level, histomorphology, follicle counts, protein expression and acetylation modification in groups of Veh, CTX, CTX-ZG and CTX-ZG-Nam (SIRT1 inhibitor).

Results: A total of 37 compounds in ZGYCF were identified. ZGYCF attenuated the morphological changes in ovarian tissue in POI model mice, increased serum AMH and E₂ levels, reduced the damage to primordial follicles and other follicles at all stages, and protected ovarian reserve. RNA-seq results suggested that the genes expression of the PI3K signaling and apoptosis signaling pathways was increased in POI mice, while ZGYCF upregulated SIRT1 gene and the expression of estradiol, apoptosis inhibition and other signaling pathway genes. Immunohistochemical staining, TUNEL staining, Western blot analysis and immunoprecipitation results showed that in CTX group, SIRT1 expression and Foxo3a nuclei localization were decreased, while Ac-Foxo3a, p-AKT, p-Foxo3a and apoptotic markers were upregulated. After administration of ZGYCF, these conditions were reversed, however, after treatment with the SIRT1 inhibitor, the results were opposite to those of ZGYCF.

Conclusions: Acetylated Foxo3a plays an important role in the occurrence of POI. ZGYCF improves the ovarian reserve of CTX-induced POI mice by activating SIRT1-mediated deacetylation of Foxo3a, and played a role in the treatment of POI. SIRT1 may be a novel target for ZGYCF to ameliorate POI.

Keywords: Deacetylation; Foxo3a; Premature ovarian insufficiency; SIRT1; Zigui-Yichong-Fang.