Perilla leaf extract prevents atopic dermatitis induced by an extract of Dermatophagoides farinae in NC/Nga mice

Perilla (Perilla frutescens Britton) leaf comprises many types of active components, mainly flavonoids, and acts as an anti-inflammatory agent in in vitro and in vivo atopic dermatitis (AD) models.We investigated the effects of orally administered perilla leaf extract (PLE) on the symptoms of AD induced by Dermatophagoides farinae extract (DFE) in NC/Nga AD model mice.The mice were allowed free intake of 0.5% PLE. Skin lesions were assessed, and blood was sampled from the caudal vein on days 0, 7, 14, 21, and 31. On day 31, all mice were sacrificed to obtain blood, skin, spleen, and intestinal tissue samples.The assessment scores of the skin lesions and total serum IgE levels of PLE-treated mice (PLE group) were significantly lower than DFE-treated mice (DFE group) on days 7, 14, and 21. On day 31, the serum periostin and thymus and activation-regulated chemokine (TARC) levels in the PLE group were significantly lower than those in the DFE group. Histological analysis of the skin revealed that hyperplasia of the epidermal and dermal layers and infiltration of inflammatory cells (cell infiltration in corium tissues) were suppressed by PLE. Periostin deposition was observed in the skin tissue obtained from the DFE group. Moreover, the CD4+/CD8+ ratio of splenic T cells was suppressed in the PLE group but not in the DFE group.