The Anti-Atopic Effects of Flavonol Content from Ginkgo biloba Leaves on NC/Nga Murine Model with Mast Cell and DNCB-induced Atopy



Hae-Young Kwon
Dept. of Beauty & Health Care
Graduate School of Daejeon University
(Directed by Prof. Kwang-Jo Cheong Ph. D)



Abstract

Gingko biloba leaf Flavonol, has been known to suppress allergic reaction, however, the cellular target of Flavonol and its mode of action remain unclear. The present study was designed to investigate the effect of Flavonol, on the murine MC/9 cell line primed with 1 μg/㎖ anti-DNP IgE overnight and stimulated by addition of 0.5 μg/㎖ DNP-HSA. For this investigation, the MC/9 cells sensitized with varying doses of MC/9 were added to the culture medium for 60 min and challenged with 0.5 μg/㎖ DNP-HSA to induce mast cell before supernatants were collected. Th2 cytokines secreted by mast cells play pivotal roles in the pathogenesis of allergic diseaes. Here we showed that treatment of MC/9 mast cells with Flavonol, significantiy suppressed 1 μg/㎖ anti-DNP IgE-induced production of Th2 cytokines including IL-13, and MIP-1a in a dose dependent manner. The mRNA expression of IL-4, IL-5, IL-13, TNF-a were completely abolished by Flavonol at the concentration of 25, 50, 100 ㎍/㎖. Results from the western blot analysis of transcription factors involving IL-13 and MIP-1a expression indicated that it prominently decreased the expression of mast cell specific transcricption factors including c-jun and NF-AT-1 but not GATA-1, GATA-2, c-fos, NF-AT-2 family and NF-kB p35. Taken together, we suggested that the anti-allergic activities of Flavonol might be mediated by down-regulation of Th2 cytokines such as IL-4, IL-5, IL-13 and MIP-1a through the regulation of transcription factors as c-jun and NF-AT-1 in MC/9 mast cells.
Atopic dermatitis(AD) usually develops in patients with an individual or family history of allergic diseases, and is characterized by chronic relapsing inflammation seen specially in childhood. Atopic dermatitis(AD) has close association with IgE hyperproduction and environmental factors. The present study examined closely the effect that Flavonol cream ointment would have in decreasing atopy dermatitis symptoms. Atopic dermatitis has many symptoms such as skin dryness, erythema, edema and erosion, dermal and epidermal thickening, hyperkeratosis, parakeratosis and inflammatory cell infiltration. Animal models induced by relevant allergens play a very important role in the elucidation of the disease. Serum total IgE levels were elevated in this model compared with normal NC/Nga mouse. After experiment, it was observed that the revelation of CD4+, CD8+, B220+CD11b+, Neutrophil+Gr-1+, and CD11b+Gr-1+ activation marker and absolute number in PBMC, ALN, were reduced. Dorsal skin establishment was recovered normal. Flavonol ointment administration decreased the numbers of IL-4, and IFN-γ in splenocytes culture supernatent, and IL-5, and IL-13 mRNA of sera and dorsal skin tissue. course inflammation immunocyte etc.. It was also observed that FK506 and Flavonol cream ointment administration to NC/Nga mouse''s dorsal skin after biopy, and dye by H&E, and toluidine staining(mast cells marker)decreased epidermis and inflamation of dermis part remarkably.
In this research, I found the fact that IL-5, IL-13, and MIP-1a expression were significantly suppressed by Flavonol. In this investigation, we demonstrated the therapeutic synergic effect of concurrent administration with Flavonol cream ointment in a mouse model, promising new therapy for atopic dermatitis. NC/Nga mouse suffered from dermatitis shows many symptoms very similar to human AD with IgE hyperproduction. So the effects that were observed during this investigation will be found when we conduct experiment targeted on human body.
This study suggests that the expression of IL-13 and MIP-1a was suppressed through the regulation of transcription factors as c-jun and NF-AT-1 pathway. In conclusion, flavonol ointment administration was therapeutically effective to chronic atopy dermatitis inflammatory diseases.