Photoprotective Effect of Taurine-Rich Protamex Extract From Salmon (Oncorhynchus keta) Byproduct Against Ultraviolet B-Induced Skin Damage in Human Dermal Fibroblasts and Zebrafish Model.

Background: Exposure to ultraviolet (UV) light promotes reactive oxygen species (ROS) production and metalloproteinase (MMP) 1 expression, leading to skin damage. Several studies have reported that protein-rich fish byproducts from enzymatic hydrolysis exhibited a variety of health benefits such as antioxidant and anti-inflammation. In the current study, we investigated the protective effect of protein hydrolysate from salmon byproduct (SBPH) in ultraviolet B (UVB)-irradiated human dermal fibroblasts (HDFs) and zebrafish.

Methods: Antioxidant activities of SBPH were evaluated by the oxidative radical scavenging assay. To determine the cytotoxicity of SBPH, the CCK-8 assay was performed. The protective effects of SBPH against photodamage was evaluated by DCF-DA, ELISA, and western blotting analysis in UVB-induced in vitro and in vivo model.

Results: SBPH significantly increased cell proliferation and suppressed UVB-induced intracellular ROS generation and MMP-1 expression by regulating activator protein 1 (AP-1) and mitogen-activated protein kinases (MAPKs) signaling pathways in HDF cells. In addition, SBPH reduced the expression of proinflammatory cytokines and alleviated the inflammatory response via suppressing nitric oxide synthase (NOS) and cyclooxygenase 2 (COX2). Moreover, UVB-induced abnormal homeostasis in HDF cells was remarkably improved via the downregulation of cell cycle regulatory proteins including p53 and p21. Furthermore, the in vivo photoprotective effect was determined by reducing the level of ROS in the UVB-induced zebrafish model.

Conclusion: These results demonstrate that SBPH possesses strong protective effects against UVB and may serve as a potential ingredient in pharmaceuticals and cosmeceuticals.