Transcriptomic evaluation of bovine granulosa obtained from peri-pubertal oocyte donors

The objective of this study is to investigate the transcriptomic signature of granulosa cells within the same animal at different age after ET program. To explore whether follicle differences are associated with age, we individually compared the effect of ovarian stimulation within the same animal at 8 and 11 months of age (peripubertal stage) and at 14 months of age (post-puberty). Overall, peripubertal donors are showing less differentiation, inflammation and apoptosis signaling which could be associated with lower basal concentration of LH. 10 young Holstein cows were used 3 times each at different ages for ovarian stimulation protocols and oocyte collections (at 8, 11 and 14 months). These oocytes were then fertilized in vitro with adult bull semen, generating 3 lots of embryos per animal. Semen from the same bull was used for all females, at all times. Each animal was used as its own control for age-effect evaluation. EmbryoGENE plateform allowed whole genome assessment of gene expression patterns at the blastocyst stage. Embryos from animals at 8 vs 14 months and at 11 vs 14 months were used for microarray hybridization. Validation was done performing RT-qPCR tests on 7 candidate genes.