Progesterone Induces Production of Reactive Oxygen Species in a Bovine Granulosa Cell Line

In cattle, low progesterone (P4) concentrations have been linked to anovulation. To study the local effects of P4 on granulosa cells, in the present study we aimed: (a) to characterise the expression of receptors (progesterone receptor (PR), oestrogen receptors α and β (ERα and β), FSH receptor (FSHR) and LH receptor (LHR)), as well as the co-expression of PR and signal transducer and activator of transcription 5 (STAT5) and a cytochrome P450 aromatase A1 (CYP19A1), in a bovine granulosa cell line (BGC-1) sensitive to P4 stimuli; and (b) to evaluate the effects of P4 on cell viability, apoptosis and reactive oxygen species (ROS) production in BGC-1 cells after 12, 24 and 48 h of stimulation. BGC-1 cells expressed CYP19A1, as well as ERα and β, PR, FSHR and LHR. The mean fluorescence intensity of STAT5 and PR and the percentage of simple and double-positive cells (STAT5/PR) were lower in control cells than in P4-stimulated cells after 12, 24, and 48 h of stimulation. Regarding the effects of P4 on cell viability, after 12, 24, and 48 h of stimulation, the percentage of living cells was high and the number of apoptotic and necrotic cells was low. Finally, BGC-1 cells responded to P4 stimulation by stimulating ROS production, without inducing damage. These results support the potential use of P4-stimulated BCG-1 cells to study the mechanisms underlying follicular persistence in cows.