Follicular fluid exosomes inhibit BDNF expression and promote the secretion of chemokines in granulosa cells by delivering miR-10b-5p.

Ovulation is an inflammatory response. Before ovulation, follicle cells release chemokines to recruit immune cells and promote ovulation. The objective of this study was to investigate whether follicular fluid exosomes promote chemokine secretion by granulosa cells (GCs). Porcine follicular fluid exosomes and follicular GCs were isolated in vitro. GCs were treated with follicular fluid exosomes in vitro and the differential gene expression profiles of the exosome-treated and control groups were obtained by transcriptome sequencing. The results showed that, when compared to the controls, the expression of the chemokines CCL2 and CXCL8 was significantly increased, whereas the expression of brain-derived neurotrophic factor (BDNF) was significantly decreased. The miRNA expression profiles in follicular fluid exosomes were obtained by microRNA sequencing. The results showed that exosomes carried many microRNAs, and that miR-10b-5p carried by exosomes could promote the secretion of CCL2 and CXCL8 by targeting BDNF. In conclusion, the present study demonstrates that exosomes promote the secretion of CCL2 and CXCL8 by granulosa cells through the miR-10b-5p/BDNF axis to promote ovulation.