Exposure to ultraviolet-B (UVB) radiation is a major contributor to skin damage and photoaging. UVB primarily induces oxidative stress and endoplasmic reticulum (ER) stress, leading to DNA instability and cellular dysfunction. Elevated reactive oxygen species (ROS) levels disrupt cellular homeostasis and activate stress-response pathways that exacerbate damage. While the effects of UVB-induced stress are well documented, strategies that enhance antioxidant defenses to simultaneously mitigate oxidative and ER stress while promoting cellular repair mechanisms, such as autophagy, remain underexplored. In this study, we investigated the protective role of antioxidant-mediated autophagy in UVB-exposed primary human dermal fibroblasts (HDFs). Our results show that UVB irradiation markedly increases ROS accumulation, triggering ER stress and DNA damage, ultimately impairing cell viability. Pharmacological enhancement of antioxidant defenses using Trolox, a vitamin E analog (α-tocopherol), effectively reduced ROS levels, alleviated oxidative and ER stress markers, and restored cellular homeostasis. Importantly, this intervention also activated autophagy, revealing a synergistic mechanism by which antioxidant and autophagic responses cooperate to protect cells. These findings establish a mechanistic link between autophagy activation and the alleviation of oxidative stress-induced ER stress, highlighting a coordinated cellular defense that mitigates DNA damage in HDFs. Collectively, our study provides valuable insights into potential therapeutic strategies aimed at enhancing skin resilience and protecting against UVB-induced damage.
