Protective effects of polysaccharides from Spirulina platensis against ultraviolet light-induced skin photoaging in KM mice and damage to mouse dermal fibroblasts

This study evaluated the potential of polysaccharides from Spirulina platensis (PSP), a blue–green microalgae with remarkable bioactive properties, as a dietary supplement for preventing UV-induced skin photoaging. PSPs were characterized by gel exclusion and ion chromatography. UV-induced skin photoaging in KM mice was treated with different doses of PSP. The potential mechanism for UV-induced damage to mouse dermal fibroblasts (MDFs) was also investigated. PSP treatment attenuated UV-induced skin damage (wrinkling, erythema, and thickening) and oxidative stress in mice and MDFs by upregulating Nrf2/HO-1/SOD2 and suppressing NF-κB/MMP pathways, suggesting dual modulation of antioxidant and anti-inflammatory mechanisms. • PSP ameliorates photoaging in KM mice skin. • PSP prevents and improves UV-induced cellular damage. • PSP activates the Nrf2/HO-1 signaling pathway and inhibits the NF-κB signaling pathway. • PSP holds potential as a dietary supplement for preventing skin photoaging.