Protective effects of γ-oryzanol against oxidative damage induced by heat stress in skin fibroblasts

γ-Oryzanol (GO), a steryl ferulate derived from rice bran oil, exhibits a broad range of biological activities. However, the mechanisms underlying GO’s protective role against heat-induced cellular stress remain largely unexplored. This study aimed to investigate the protective effects of GO against heat stress in human foreskin fibroblast (HFF2) cells. HFF2 cells were exposed to heat stress (43 °C) in the presence or absence of 100 µg/mL GO, and cell viability, reactive oxygen species (ROS), glutathione (GSH), and nuclear factor erythroid 2–related factor 2 (Nrf2) expression were evaluated. Heat stress significantly increased intracellular ROS levels (~2.8-fold, p < 0.01), decreased GSH levels (p < 0.01), and upregulated Nrf2 expression. Treatment with 100 µg/mL GO significantly improved cell viability (p < 0.05), reduced ROS levels (p < 0.01), increased GSH content by approximately 1.35-fold (p < 0.05), and reduced Nrf2 expression by approximately 40% compared with heat-stressed cells. These findings suggest that GO protects skin fibroblasts against heat-induced oxidative damage by restoring cellular redox homeostasis and modulating antioxidant defense mechanisms.