Moxibustion ameliorates ovarian function in premature ovarian insufficiency rats by activating cAMP/PKA/CREB to promote steroidogenesis in ovarian granulosa cells

Premature ovarian insufficiency (POI) presents a substantial challenge to women's physiological and psychological well-being. Hormone replacement therapy, as the preferred therapeutic approach, involves solely exogenous supplementation of estrogen. Moxibustion, a traditional Chinese external treatment, has been investigated in our previous studies. It not only improves hormone levels and clinical symptoms in POI patients but also safeguards ovarian reserve. This study aims to explore the regulatory mechanisms by which moxibustion modulates hormone levels and restores ovarian function in POI. A POI rat model was established using cyclophosphamide, and moxibustion treatment was applied at acupoints "CV4" and "SP6" for a total of four courses. Subsequently, ovaries from each group were subjected to transcriptome sequencing (Bulk RNA-seq). Target pathways and key genes were selected through enrichment analysis and GSVA scoring, with validation using various techniques including electron microscopy, ELISA, Western blot, and immunohistochemistry. The results demonstrated that moxibustion restored the estrous cycle in POI rats, improved sex hormone levels, reduced the number of atretic follicles, and increased the count of dominant follicles (P<0.05). Bulk RNA-seq analysis revealed that moxibustion downregulated pathways associated with ovarian dysfunction, infertility, and immune responses, upregulated pathways related to follicular development and ovarian steroidogenesis. Furthermore, our data confirmed that moxibustion significantly increased the number of ovarian granulosa cells (GCs) and upregulated the expression of proteins related to steroidogenesis in GCs, including FSHR, P450 arom, cAMP, PKA, and CREB (P<0.05), with no significant effect observed on proteins related to steroidogenesis in theca cells. These outcomes aligned with the RNA-seq results. In conclusion, these findings propose that moxibustion enhances steroidogenesis in GCs through the activation of the cAMP/PKA/CREB pathway, consequently improving impaired ovarian function in POI rats. This study provides robust evidence supporting moxibustion as a targeted intervention for treating POI by specifically regulating steroidogenesis in GCs.