Differential Antioxidant Capacities of Human Endometriotic and Endometrial Cell Models Under H₂O₂ Exposure

Endometriosis is associated with oxidative stress and debilitating symptoms, yet its pathophysiology remains incompletely understood, and current treatments are still limited. In this study, oxidative stress responses were compared in 2D and 3D cultures of 12Z and Ishikawa cells using hydrogen peroxide (H₂O₂) as a pro-oxidant and N-acetylcysteine (NAC) as an antioxidant. We evaluated H₂O₂ sensitivity, Reactive Oxygen Species (ROS) production, glutathione redox homeostasis, and biomolecular damage. The results showed that 12Z cells display greater vulnerability to oxidative stress than Ishikawa cells, with higher basal ROS levels (p < 0.01) and increased sensitivity to H₂O₂. In 3D culture, 12Z cells exhibited a 72% depletion of total glutathione under oxidative stress, a response not observed in 2D cultures, which instead showed a compensatory pattern. This vulnerability was further supported by increased lipid peroxidation and protein carbonylation. Although NAC restored cell viability and protected lipids and proteins, it did not prevent DNA damage. Together, these findings demonstrate marked differences in antioxidant responses between the two cell models and reinforce the value of 3D systems for investigating oxidative stress-related mechanisms. These results provide mechanistic insights relevant to endometriosis-associated redox imbalance and support further investigation of glutathione dysregulation and ROS-mediated damage in disease-related contexts.