Oxidative Stress Triggers Porcine Ovarian Granulosa Cell Apoptosis Through MAPK Signaling.

Follicle health determines the number and quality of sows' ovulation, thereby influencing the litter size and the piglets' viability. Granulosa cells (GCs) play a crucial role in follicular formation and development, and oxidative stress-induced GC death is a major cause of follicular dysplasia. Previous studies have confirmed that oxidative stress triggers apoptosis in granulosa cells. In this study, we explored how oxidative stress influences apoptosis in porcine ovarian granulosa cells. We find that porcine atretic follicles exhibit significant oxidative stress, accompanied by the activation of the mitogen-activated protein kinase (MAPK) signaling pathway, including the upregulation of key factors such as apoptosis signal-regulating kinase 1 (ASK1). Healthy follicles of 3-5 mm were randomly assigned to the control group, HO treatment group, and selonsertib pretreatment group. The porcine ovarian GCs were placed in cell culture medium supplemented with HO to assess ROS production, cell proliferation, apoptosis, the expression levels of oxidative stress-related genes, and expression levels of apoptosis-related proteins. In vitro experiments in mouse GCs further confirmed that HO-induced oxidative stress triggers the upregulation of the MAPK pathway and promotes granulosa cell apoptosis. The results showed that HO treatment induced ROS production and apoptosis in porcine GCs and inhibited GC viability. Additionally, selonsertib pretreatment attenuated apoptosis in GCs by inhibiting HO-induced oxidative stress. In summary, our findings reveal that oxidative stress induced granulosa cell apoptosis via the MAPK signaling pathway, impairing proper follicular development in pigs.