Ameliorative effects of squid phospholipids from Todarodes pacificus on atopic dermatitis-like lesions in NC/Nga mice

Atopic dermatitis (AD), also known as eczema, is a chronic or relapsing inflammatory skin disease characterized by repeated exacerbations and remissions. Here, we investigated the effects of squid phospholipids (PLs) extracted from Todarodes pacificus on AD. The composition of squid PLs was analyzed using thin-layer chromatography and high-performance liquid chromatography, and the effects of PLs on AD were investigated using a rat paw edema model and an AD-like mouse model (NC/Nga mice). Squid PLs mainly consist of phosphatidylethanolamine (PE), phosphatidylcholine (PC), docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and arachidonic acid, which are bound at the sn-2 positions of PE and PC. Squid PLs inhibited rat paw edema induced by platelet-activating factor, a highly potent pro-inflammatory mediator. In an AD mouse model (NC/Nga mice), the topical application of squid PLs (1% or 5%) improved dermatitis of the ears and reduced thickness of the ears and epidermis in dermatitis, but 1.2% DHA or 1% soybean PC did not affect them. There results suggest that squid PLs, which mainly consist of PC and PE, and contain DHA, EPA, and ARA at the sn-2 position, may be useful for the prevention and treatment of AD.