Oxidative Stress in Animals: A Systematic Analysis from Signaling Pathways to Biological Effects

Oxidative stress is caused by the imbalance between the generation of free reactive oxygen species (ROS)/reactive nitrogen species (RNS) and the antioxidant defense systems, which participate in animal growth, development, disease pathogenesis, and aging. This review summarizes endogenous and exogenous triggers of ROS/RNS overproduction, as well as model animals and cell models together with oxidative stress biomarkers and detection methods. We further dissect the three-layered redox regulatory network, focusing on crosstalk among four core pathways (Nrf2-ARE, NF-κB, MAPK, PI3K/Akt) that govern cell fate via oxidative eustress or distress. Excessive ROS/RNS trigger irreversible DNA damage and metabolic disorders, leading to inflammation and apoptosis. Finally, we prospect integrating non-model animals and multi-omics to advance oxidative stress research. This work provides a comprehensive theoretical framework for animal redox biology studies.