Abstract
BACKGROUND: Photoaging, induced by chronic ultraviolet (UV) exposure, is a multifactorial skin disorder characterized by oxidative stress, inflammation, and extracellular matrix degradation. Ganoderma lucidum glycoprotein (Gl-Gp) exhibits potent antioxidant activity, but its topical application is limited by poor transdermal permeability. This study aimed to develop a microemulsion-based system to enhance Gl-Gp delivery and evaluate its anti-photoaging efficacy. METHODS: Gl-Gp was extracted and purified from G. lucidum fruiting bodies and structurally characterized for O-glycosidic linkages and O-GlcNAc modifications. Fourier-transform infrared (FT-IR) spectroscopy further confirmed the polysaccharide-protein complex structure of Gl-Gp. A water-in-oil Gl-Gp microemulsion was prepared and assessed in vitro for antioxidant and cytoprotective effects in HaCaT cells, including reactive oxygen species (ROS) reduction, mitochondrial membrane potential stabilization, and apoptosis inhibition. Transdermal penetration was compared with aqueous Gl-Gp. In vivo efficacy was evaluated in a UV-induced rat model by measuring skin morphology, histology, oxidative stress markers, matrix metalloproteinases, and proinflammatory cytokines. RESULTS: The microemulsion enhanced Gl-Gp stability and transdermal delivery. In vitro, it reduced ROS, preserved mitochondrial function, and decreased apoptosis in HaCaT cells. In rats, topical application attenuated erythema and epidermal hyperplasia, promoted dermal restoration, increased SOD and GSH-Px activities, and decreased MDA, hydroxyproline, MMPs, and inflammatory mediators. CONCLUSIONS: The Gl-Gp microemulsion exerts antioxidant, anti-inflammatory, and anti-collagen-degrading effects, representing a promising strategy for transdermal delivery and topical prevention of photoaging.