Inhibitory effects of Saururus chinensis (LOUR.) BAILL on the development of atopic dermatitis-like skin lesions in NC/Nga mice

The present study was performed to examine whether the leaves of Saururus chinensis (LOUR.) BAILL (SC), an herb used for the management of various skin diseases including atopic dermatitis (AD) in Eastern countries, inhibited the development of AD-like skin lesions in NC/Nga mice which was induced by repeated application of picryl chloride (PiCl). The efficacy of SC was judged by measurement of skin severity, itching behavior, histological study, serum IgE levels, IL-4 and IFN-gamma in lymph nodes. Oral administration of SC extract to the PiCl-treated NC/Nga mice for 8 weeks (5 d per week) inhibited significantly the development of AD-like skin lesions macroscopically. Histologically, SC inhibited dermatitis changes like hypertrophy, hyperkeratosis, and infiltration of inflammatory cells into epidermis and dermis. The itching behavior and serum IgE level decreased significantly after SC administration. SC administration enhanced IFN-gamma mRNA expression but did not have an effect on IL-4 mRNA expression. These results suggest that SC could inhibit the development of AD-like skin lesions in NC/Nga mice possibly through modulating the Th1/Th2 imbalance by the promoting of Th1 cell response. Thus, SC may be an alternative substance for the management of AD patients.