Utilizing Extracellular Vesicles from Phaeodactylum tricornutum as a Novel Approach for Protecting the Skin from...

Oxidative stress is a principal factor contributing to skin damage induced by deleterious stimuli, including ultraviolet (UV) radiation. Microalgae-derived extracellular vesicles (EVs), particularly those from Phaeodactylum tricornutum (PTEV), are gaining recognition as a potential therapeutic avenue for restoring skin homeostasis, owing to their scalable production and multifaceted biological activities. This study evaluates the therapeutic effects of PTEV on oxidative damage in H₂O₂-stimulated HaCaT cells and UV-exposed KM mouse models, based on the extraction and characterization of PTEV. Subsequently, the oxidative stress injury model of HaCaT cells induced by H₂O₂ and the acute photodamage model of KM mice skin induced by UV were established. The results show that HaCaT cells exhibit a time-dependent uptake of PTEV, confirming that PTEV is nontoxic and has the potential for intercellular cross-boundary regulation. Treatment with PTEV can enhance the vitality of H₂O₂-stimulated HaCaT cells, reduce intracellular ROS levels, and increase antioxidant enzyme activity in the cells. Further evaluation revealed that PTEV can inhibit UV-induced thickening of the epidermis and degradation of collagen fibers in mice by suppressing the overexpression of matrix metalloproteinase (MMP-3) induced by UV. It enhances the expression of type I collagen (COL1A1) and increases the activity of antioxidant enzymes, as well as the overall antioxidant capacity of tissues. Additionally, PTEV reduces the increase in malondialdehyde levels and lowers the expression levels of inflammatory factors TNF-α and IL-6, thereby protecting the skin barrier and function in mice with acute photodamage. Continuous production of PTEV offers promising applications in therapeutic strategies.