Tumor necrosis factor alpha inhibits ovulation and induces granulosa cell death in rat ovaries

PURPOSE: We evaluated the role of tumor necrosis factor alpha (TNFα) in rat ovulation and granulosa cell death of ovarian follicles during the periovulatory stage. METHODS: Immature rats primed with pregnant mare serum gonadotropin were injected intraperitoneally with human chorionic gonadotropin (hCG), and TNFα was injected into the bursa 48 h later. The total number of released oocytes was counted. Apoptosis was measured with terminal deoxynucleotidyl transferase‐mediated dUTP nick end labeling (TUNEL) and the expression of cleaved caspase 3 and Bax/Bcl‐2. Autophagy was assessed by the expression of light chain protein 3 (LC3) and autophagosomes under transmission electron microscopy. RESULTS: TNFα significantly decreased the number of released oocytes, and many unruptured follicles were observed. TUNEL analysis revealed a larger number of apoptotic cells, and the cleaved caspase 3 and Bax/Bcl‐2 increased more than that of the control 12 h after hCG administration. Furthermore, the expression of LC3 wwas significantly higher than that of the control, and autophagosomes were observed in the cytoplasm. CONCLUSIONS: Our data indicated that TNFα is an important mediator of ovulation in terms of decreasing the number of released oocytes and inducing granulosa cell death of unruptured follicles via apoptosis and autophagy for remodeling ovarian tissues.