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.长期以来，哺乳动物中细胞凋亡（apoptosis）被认为是发生于闭锁卵巢卵泡中的程序性细胞死亡（Programmed Cell Death, PCD）类型。然而，近期研究表明自噬（autophagy）或许是参与卵泡耗竭的另一机制，可独立于细胞凋亡或与之协同发挥作用。本研究通过蛋白质印迹法（Western Blot）与免疫荧光法（Immunofluorescence），检测新鲜采集的颗粒细胞（Granulosa Cells, GC）、卵丘细胞（Cumulus Cells, CC）及卵母细胞中LC3B蛋白的表达水平，以评估自噬在性成熟母猪有腔卵泡闭锁过程中的作用。此外，本研究采用膜联蛋白V（Annexin V）与脱氧核糖核苷酸末端转移酶介导的缺口末端标记法（Terminal deoxynucleotidyl transferase dUTP nick end labeling, TUNEL）检测法，对同一细胞群中的细胞凋亡进行分析，以探究这两种过程之间的相关性。免疫染色结果显示，从早期及晚期闭锁卵泡中采集的大部分颗粒细胞、卵丘细胞及卵母细胞中均诱导产生了自噬。蛋白质印迹法的定量分析结果表明，与健康卵泡来源的细胞相比，闭锁卵泡来源的上述细胞中，自噬相关蛋白形式LC3B-II的表达水平呈显著（P < 0.05）且进行性升高。此外，本研究数据证实，闭锁卵泡的颗粒细胞中存在细胞凋亡，这表明与大鼠及人类相似，猪的颗粒细胞中细胞凋亡与自噬作为程序性细胞死亡的协同过程，共同介导有腔卵泡的耗竭。最后，本研究未在闭锁卵泡的卵丘细胞及卵母细胞中检测到细胞凋亡，但却检测到LC3B-II的过表达，因此我们推测，在这两类细胞中，两种过程独立发挥作用，自噬作为一种细胞保护机制而非程序性细胞死亡机制参与其中。