Stressor-specific mitochondrial responses in bovine endometrium-derived cells reveal dissociation between oxidative...

Inflammatory and environmental stressors can compromise uterine function and fertility. Mitochondria are central regulators of energy metabolism, redox balance, and stress adaptation; however, it remains unclear whether the magnitude of oxidative stress predicts mitochondrial outcomes in endometrium-derived cells exposed to different stress contexts. In this study, bovine endometrium-derived cells were exposed to lipopolysaccharide (LPS), hydrogen peroxide (H₂O₂), or heat stress (41 °C), followed by overnight recovery. Mitochondrial-associated responses were assessed by measuring intracellular reactive oxygen species (ROS), MitoTracker Red fluorescence, total cellular ATP content, mitochondrial DNA copy number, and mitochondrial protein-coding gene expression. All stress conditions increased ROS levels, with the highest levels observed after H₂O₂ exposure. However, ROS accumulation was not consistently associated with the extent of mitochondrial alterations across stress conditions. H₂O₂ treatment was associated with lower MitoTracker Red fluorescence than heat stress, whereas LPS specifically reduced total cellular ATP content after recovery. Both LPS and H₂O₂ increased mitochondrial DNA copy number, while heat stress had no significant effect. Inflammatory stress was also associated with reduced mitochondrial respiratory chain transcript abundance, whereas oxidative and heat stress were compatible with preservation of mitochondrial transcriptional balance after recovery. These findings indicate that stressor-specific mitochondrial states may arise despite shared oxidative burden, with inflammatory stress showing the most pronounced alterations after recovery under the conditions tested.