Differentially Expressed Genes Associated with Primordial Follicle Formation and Transformation to Primary Follicles

Objective: Primordial follicle assembly and the transition from primordial follicle to primary follicle are critical processes in ovarian biology. These processes determine the size of the primordial follicle pool, which may limit the reproductive lifespan of a female. When the follicle pool is depleted, reproduction ceases and females enter menopause. In this study, we aimed to explore the role of differentially expressed genes (DEGs) in the processes of primordial follicle assembly and the transfonnation from primordial to primary follicle. Methods: The gene chip GSE9300 was downloaded from the Gene Expression Omnibus database. DEGs between ovaries on postnatal day 0 and ovaries on postnatal day 4, as well as ovaries on postnatal day 4 and ovaries cultured for 7 days from postnatal day 0 were identified. Gene ontology (GO), pathway enrichment analysis, and protein-protein interaction network construction were performed. Results: In total, 99 upregulated genes and 123 downregulated genes were identified in the process of primordial follicle assembly, and 101 upregulated genes and 98 downregulated genes were identified in the process of transfonnation from primordial to primary follicle. The GO analysis showed that response to estradiol was associated with two of the processes of assembly and subsequent development of primordial follicle, but the genes involved in response to estradiol between the two processes were significantly different. Furthermore, the two groups of DEGs were all associated with metabolic pathways. Conclusions: DEGs may provide new insights into the exploration of mechanisms related to primordial follicle assembly and subsequent development.