Inhibitors of c-Jun phosphorylation impede ovine primordial follicle activation.

Study Hypothesis: Is the c-Jun-N-terminal kinase (JNK) pathway implicated in primordial follicle activation?

Study Finding: Culture of ovine ovarian cortex in the presence of two different c-Jun phosphorylation inhibitors impeded pre-antral follicle activation.

What Is Known Already: Despite its importance for fertility preservation therapies, the mechanisms of primordial follicle activation are poorly understood. Amongst different signalling pathways potentially involved, the JNK pathway has been previously shown to be essential for cell cycle progression and pre-antral follicle development in mice.

Effects of bone morphogenetic protein 4 (BMP4) supplementation during culture of the sheep ovarian cortex.

The aim of the present study was to establish the presence of BMP type I and II receptor presence in preantral follicles and to investigate the effect of BMP4 supplementation on preantral follicle activation and development during organotypic culture of prepubertal ovine ovarian cortex pieces. Ovine ovarian fragments were cultured with varying concentrations (0, 25, 50 or 100 ng/ml) of BMP4 in the presence or absence of FSH in the culture media to determine the optimal minimum dose for preantral follicle activation and development. Follicular morphometry, immunohistochemistry for BMPR-IA, BMPR-IB, BMPR-II, proliferating cell nuclear antigen and TUNEL progesterone and 17β-oestradiol production were assessed.