Pyrus ussuriensis Maxim. leaves extract ameliorates DNCB-induced atopic dermatitis-like symptoms in NC/Nga mice

Abstract

Purpose: Pyrus ussuriensis Maxim. has been reported to treat the fever, cough, asthma, and chronic skin disease in Korean Medicine. However, there is no scientific evidence for the use of Pyrus ussuriensis Maxim. Leaves (PUL) extract or its mechanism of action in atopic dermatitis (AD). This study was performed to find the potential therapeutic effects of PUL on the progression of AD using in vitro and in vivo experimental models.

Methods: We examined the effects of PUL on the production of nitric oxide (NO) in RAW 264.7, Interleukin 6 (IL-6) and Interleukin 1β (IL-1β) in tumor necrosis factor α (TNF-α) -induced HaCaT cells, respectively. The PUL extract was topically administered to the 2,4-Dinitrochlorobenzene (DNCB) -treated NC/Nga mice. The potential effects of PUL extract were evaluated by measuring the dermatitis score, scratching behavior and serum levels of immunoglobulin E (IgE). The Interleukin 4 (IL-4) and Interleukin 13 (IL-13) cytokines levels were also measured in the splenocytes. In addition, the major components from PUL were analyzed using high performance liquid chromatography (HPLC).

Results: PUL extract significantly reduced the level of NO in RAW 264.7 cells, as well as IL-6 and IL-1β in TNF-α-induced HaCaT cells. It also reduced IL-4 and IL-13 levels in splenocytes. In DNCB-treated NC/Nga mice, PUL extract significantly ameliorated the dermatitis severity, scratching tendency and transepidermal water loss (TEWL) compared to the negative control. Also, it normalized skin barriers with decreased production of IgE in mice serum. The arbutin, chlorogenic acid, and rutin were identified as major constituents of the extract by HPLC analysis. These constituents may be involved either alone or together in the regulation of atopic dermatitis.

Conclusion: Our studies indicate that PUL ameliorates atopic dermatitis-like symptoms by suppressing the proinflammatory cytokines and immune stimuli in both in vitro and in vivo animal models. Therefore, these data suggest that PUL might be an effective natural resource for the treatment of AD.

Keywords: 2, 4-dinitrochlorobenzene; Atopic dermatitis; IgE; Interleukins; NC/Nga mice; Pyrus ussuriensis Maxim.