A novel liposomal hydrogel loaded with deer blood peptides prevents UVB-induced skin photoaging

Ultraviolet (UV) irradiation is a major global contributor to skin damage. To identify novel protective agents, this study evaluated the photoprotective effects of deer blood peptides (DBP) and developed a DBP-based delivery system to prevent UV-induced skin photoaging. DBP was extracted from deer blood via enzyme hydrolysis. In vitro cytotoxicity and cell apoptosis assays confirmed the safety of DBP, while radical scavenging assays and measurements of intracellular reactive oxygen species (ROS) demonstrated its strong antioxidant capacity. Owing to its nutrient-rich composition, potent antioxidant activity, and ability to promote cell proliferation, DBP shows great promise for photoaging therapy. Compared with the free DBP and liposomal DBP (DBP-Lip), the optimized liposome-hydrogel formulation (DBP-Lip-Gel) exhibited superior antioxidant capacity, enhanced skin permeability, and improved stability. In vivo, pretreatment with DBP-Lip-Gel resulted in smoother skin, with histopathological analysis showing a marked reduction in epidermal thickening. Further biochemical assessments revealed that DBP increased glutathione and superoxide dismutase activity while attenuating the UVB-induced elevation of ROS, malondialdehyde, interleukin-1, interleukin-6, and tumour necrosis factor-α. Mechanistic investigations also identified key signaling pathways underlying its photoprotective effects. In conclusion, DBP-Lip-Gel effectively alleviates UVB-induced skin photoaging, underscoring its potential for medical and dermatological applications.