Data for: Expression of the autophagy-related protein LC3B in granulosa cells, cumulus cells, and oocyte during atresia of pig antral follicles
For a long time, in mammals apoptosis was accepted as the type of programmed cell death (PCD) occurring in ovarian follicles undergoing atresia. However, recent studies have suggested that autophagy may be an alternative mechanism involved in follicle depletion, working independently or in tandem with apoptosis. This research investigated by western blot and immunofluorescence the expression of LC3B protein in freshly collected granulosa cells (GC), cumulus cells (CC), and oocytes to evaluate the involvement of autophagy in the process of antral follicle atresia in sexually mature sows. Moreover, apoptosis was analysed by Annexin V and TUNEL assays in the same cellular cohorts to evaluate the correlation between the two processes. Our immunostaining results show that the autophagy is induced in the majority of GC, CC, and oocytes collected from early and advanced atretic follicles. The quantitative results of western blot analysis demonstrate that a significant (P < 0.05) and progressive increase of expression of the autophagy-related form of the protein (LC3B-II) takes places in these cells compared to healthy ones. Moreover, our data confirm that apoptosis occurs in GC of atretic follicles, thus showing that in pigs, like in rats and humans, apoptosis and autophagy work in GC as combined processes of PCD for antral follicle depletion. Finally, we did not detect apoptosis whereas we detected an overexpression of LC3B-II in CC and oocytes of atretic follicles, thus we suggest that in these cells the two processes work independently, with autophagy acting like a cytoprotective rather than a PCD mechanism.