A Sponge-like Polysaccharide from Pine Pollen: Structural Features and Therapeutic Potential in DNCB-Induced Atopic Dermatitis Models

<b>Objectives:</b> Atopic dermatitis (AD) is a long-term, recurring inflammatory skin condition characterized by impaired epidermal barrier function and abnormal immune system regulation. Pine pollen has traditionally been used for dermatological treatments, though its active components remain unclear. The primary objective of this study was to pinpoint the active constituents of pine pollen and elucidate its therapeutic effects against AD. <b>Methods:</b> The safety concentration ranges and protective efficacy of nine pine pollen constituents against 2,4-dinitrochlorobenzene (DNCB)-induced HaCaT cell damage were evaluated using the CCK-8 assay. Furthermore, models of DNCB-induced damage were established both in vitro (HaCaT cells) and in vivo (BALB/c mice) to explore the protective effects of the key functional component. <b>Results:</b> Our findings identified pine pollen polysaccharides (PPPS) as the principal bioactive constituent, characterized by a unique infrared absorption spectral profile and a sponge-like architecture with three-dimensional interconnected porous networks. In vitro, PPPS inhibited DNCB-induced decreases in cell viability, morphological abnormalities, oxidative stress, and apoptosis. In vivo, PPPS alleviated DNCB-induced skin lesions by attenuating epidermal hyperplasia, suppressing mast cell infiltration, inhibiting cell apoptosis, and downregulating the expression of IL-4 and IL-17A. <b>Conclusions:</b> This study provides evidence that PPPS from pine pollen can alleviate epidermal damage in AD, offering a novel therapeutic strategy for AD treatment.