RESUMO
N-Hexane causes significant ovarian toxicity, and its main active metabolite 2,5-hexanedione (2,5-HD) can induce ovarian injury through mechanisms such as inducing apoptosis in ovarian granulosa cells (GCs); however, the specific mechanism has not been fully elucidated. In this study, we investigated the effects on the cell cycle of rat ovarian GCs exposed in vitro to different concentrations of 2,5-HD (0 mM, 20 mM, 40 mM, and 60 mM) and further explored the mechanism by mRNA and miRNA microarray analyses. The flow cytometry results sindicated that compared with control cells, in ovarian GCs, there was significant cell cycle arrest after 2,5-HD treatment. Cell cycle- and apoptosis- related gene (Cdk2, Ccnd1, Bax, Bcl-2, Caspase3, and Caspase9) expression was altered. The mRNA and miRNA microarray results suggested that 5678 mRNAs and 32 miRNAs were differentially expressed in the 2,5-HD-treated group. A total of 262 target mRNAs were obtained by miRNA and mRNA coexpression analysis, forming 368 miRNA-mRNA coexpression relationship pairs with 27 miRNAs. GO and KEGG analyses showed that differentially expressed genes were significantly enriched in the cell cycle and Wnt signaling pathways. Furthermore, significant changes in the expression of Wnt signaling pathway and cell cycle- related genes (Fzd1, Lrp6, Tcf3, Tcf4, Fzd6, Lrp5, ß-catenin, Lef1, GSK3ß, and Dvl3) after 2,5-HD treatment were confirmed by qRT-PCR and Western blotting. Ther results of dual-luciferase assays indicated decreased ß-catenin/TCF transcriptional activity after 2,5-HD treatment. In addition, Wnt pathway-related miRNAs (rno-miR-145-5p, rno-miR-143-3p, rno-miR-214-3p, rno-miR-138-5p, and rno-miR-199a-3p) were changed significantly after 2,5-HD treatment. In summary, 2,5-HD induced cell cycle arrest in ovarian GCs, and the Wnt/ß-catenin signaling pathway may play a very critical role in this process. Alterations in the expression of miRNAs such as rno-miR-145-5p may have significant implications.
