Objective: Previous studies have shown the importance of apoptosis in follicular atresia occurring especially in granulosa cells (GC) and its relation to the outcome of in vitro fertilization (IVF). The aim of this study was to evaluate the effects of a Gonadotropin-Releasing Hormone agonist (GnRHa) and of Follicle-Stimulating Hormone (FSH) on the apoptosis rate of human luteinized GC.
Study design: GC were isolated from follicular fluids of 15 women undergoing IVF cycles, cultured for 1 day and then treated for 1 day in serum-free medium with triptorelin at 100 or 1000pg/ml or with FSH at 100 or 500ng/ml. GC cultured without any hormone addition were used as controls. Treatment of cultured GC with triptorelin 100pg/ml and FSH 100ng/ml was performed five times each. GC were analysed by flow cytometry after propidium iodide staining to measure the percentage of apoptotic GC. Some triptorelin-treated GC were also examined by electron microscopy.
Results: Percentages of GC apoptosis were after hormone treatment respectively: FSH: 100ng/ml, 2.9+/-0.6%; 500ng/ml, 2.9%; triptorelin: 100pg/ml, 18.6+/-2.8%; 1000pg/ml, 86.5% versus 9.8+/-1.8% in GC controls (FSH 100ng/ml versus control; triptorelin 100pg/ml versus control: P<10(-6)). Electron microscopy confirmed apoptosis of GC incubated with triptorelin.
Conclusions: This study demonstrated that FSH decreased apoptosis in human luteinized GC. In contrast, triptorelin was possibly implicated in a dose-dependent increase in the incidence of apoptotic GC. This last result suggests that clinical use of GnRHa should perhaps be reconsidered in the context of its apoptosis-inducing effect.