RESUMO
BACKGROUND: Platycodon grandiflorum is a traditional Asian medicine that is used to treat pulmonary and respiratory allergic disorders. OBJECTIVE: to investigate the effects of P grandiflorum in vivo in an animal model of atopic dermatitis (AD), with particular emphasis on its effects on T(H)1 and T(H)2 immune responses. METHODS: we established a model of AD-like skin lesions in NC/Nga mice. After oral administration of P grandiflorum, we measured cytokine and immunoglobulin profiles along with histologic examination of skin. RESULTS: P grandiflorum was nontoxic in a 2,4-dinitrofluorobenzene-induced model of AD-like skin lesions in NC/Nga mice. AD symptoms in skin lesions improved after oral administration of P grandiflorum. IgE secretion was significantly downregulated in P grandiflorum-treated animals, accompanied by decreased levels of interleukin (IL) 4 and IgG1 and increased serum levels of IL-12p40 and IgG2a. In isolated splenocytes, the production of the T(H)1 cytokines IL-12p40 and interferon-γ was upregulated by P grandiflorum, whereas the levels of the T(H)2 cytokines IL-4 and IL-5 were downregulated in a mouse model of AD-like skin lesions. CONCLUSIONS: these results suggest that P grandiflorum inhibits the development of AD-like skin lesions in NC/Nga mice by suppressing the T(H)2 cell response and increasing the T(H)1 cell responses. Our results indicate that P grandiflorum is safe and effective as a natural herbal medicine for the treatment of AD-like skin lesions.
