Inhibition of atopic dermatitis by topical application of silymarin in NC/Nga mice

Silymarin has been known to inhibit chemical-induced irritant contact dermatitis. In the present study, we report that topical application of silymarin suppresses dust mite extract (DPE)-induced atopic dermatitis (AD) in NC/Nga mice. Repeated topical application of ears with DPE caused AD-like skin lesions in NC/Nga mice. However, silymarin reduced AD-like skin lesions in these mice, resulting in decreased ear swelling and leukocyte infiltration into the ear. Moreover, our results showed that mast cell infiltration into the ear was suppressed by silymarin treatment in DPE-treated NC/Nga mice. Silymarin also reduced plasma level of IL-4 and IgE in these mice. Further study demonstrated that the mRNA expression of IL-4 was increased and that of IFN-gamma was decreased by DPE treatment in the ears of NC/Nga mice. However, DPE-induced changes in IL-4 and IFN-gamma mRNA expression were reversed by silymarin. DPE-induced increase in TNF-alpha mRNA expression was also suppressed by silymarin treatment. The results presented in this report suggest that silymarin might be beneficial for the treatment of AD.     

DA-9601 suppresses 2, 4-dinitrochlorobenzene and dust mite extract-induced atopic dermatitis-like skin lesions

DA-9601 (Stillen?) is a novel anti-peptic formulation prepared from the ethanol extracts of Artemisia asiatica possessing anti-oxidative, anti-allergic and anti-inflammatory activities. However, their effect on atopic dermatitis (AD) has not been studied yet. In this study, we report that topical application of DA-9601 suppressed house dust mite extract (Dermatophagoides farinae extract, DFE) and 2, 4-dinitrochlorobenzene (DNCB)-induced AD-like skin lesions in BALB/c mice model. We established atopic dermatitis model in BALB/c mice by repeated local exposure of DFE/DNCB to the ears. Repeated alternative treatment of DFE/DNCB caused AD-like lesions. DA-9601 reduced AD-like skin lesions based on ear thickness and histopathological analysis, and serum IgE levels. DA-9601 inhibited mast cell infiltration into the ear and elevation of serum histamine in AD model. In addition, DA-9601 suppressed DFE/DNCB-induced expression of IL-4, IL-13, IL-31, and TNF-α in the ears. Taken together, our results showed that topical application of DA-9601 exerts beneficial effects in animal model of AD, suggesting that DA-9601 might be a candidate for the treatment of AD.     

Effects of topically applied Korean red ginseng and its genuine constituents on atopic dermatitis-like skin lesions in NC/Nga mice

Ginseng (the root of Panax ginseng C.A. Meyer, family Araliaceae) possesses various biological activities, including anti-inflammatory and anti-tumor actions. However, their topical effect on atopic dermatitis (AD) has not been studied yet. The aim of this study was to examine the therapeutic effects of topical Korean red ginseng saponin fraction (KRGS) and its genuine constituents on AD-like skin lesions in an AD mouse model. The therapeutic effect of topical KRGS and ginsenosides in 2-chloro-1,3,5-trinitrobenzene (TNCB)-treated NC/Nga mice was assessed by measuring the skin severity scores, ear thickness, histological changes of lesional skin including mast cell count, tissue tumor necrosis factor (TNF)-α, interleukin (IL)-4, and interferon (IFN)-γ mRNA expression, and total serum IgE. Topical administration of 0.1% KRGS, 0.1% Rh2 and 0.1% Rh2+0.1% Rg3 significantly reduced the clinical skin severity scores, ear thickness and mast cell infiltration in the TNCB-induced AD-like skin lesions. Topical application of KRGS and its constituents significantly reduced TNCB-induced increase in ear TNF-α and IL-4 mRNA expression, but not IFN-γ mRNA expression. There was little change of serum total IgE level by topical KRGS and its constituents. In this study, topical KRGS and ginsenosides Rh2 and Rg3 were found to exert an anti-inflammatory effect in vivo and proved to be beneficial in an animal model of AD. Our results suggest that KRGS and its ginsenosides Rh2 and Rg3 have potential as a topical agent for the treatment of AD.     

Improvement of Atopic Dermatitis-Like Skin Lesions by <i>Platycodon grandiflorum</i> Fermented by <i>Lactobacillus plantarum</i> in NC/Nga Mice

Atopic dermatitis (AD) is characterized as a multi-factorial inflammatory skin disease that has been increasing worldwide. Previously, we demonstrated that FPG, which is Platycodon grandiflorum (PG) fermented by Lactobacillus plantarum (LP), increases the level of interferon (IFN)-gamma in mouse splenocytes in vitro. In this study, we investigated the effects of FPG in an animal model of AD, with a particular emphasis on its effects on T helper (Th)1 and Th2 immune responses. To assess the potential use of FPG for the inhibition of AD, we established a model of AD-like skin lesions in NC/Nga mice. Immunoglobulin isotypes (Igs) and Th1/Th2 cytokines in the sera and spleens of AD-like mice were examined. In addition, histological examination was also performed. AD symptoms in skin lesions improved following oral administration of FPG. IgE secretion was significantly down-regulated, and this was accompanied by decreased levels of interleukin (IL)-4 and IgG1 and increased serum levels of IL-12p40 and IgG2a in FPG-treated animals. In splenocytes, the production of the Th1 cytokines IL-12p40 and IFN-gamma was up-regulated, while the levels of the Th2 cytokines IL-4 and 5 were down-regulated by FPG treatment. These results suggest that FPG inhibits the development of AD-like skin lesions in NC/Nga mice by suppressing the Th2 cell response and increasing the Th1 cell responses. Our results indicate that FPG is safe and effective for the prevention of AD-like skin lesions.     

Inhibitory effect of galangin on atopic dermatitis-like skin lesions

Galangin is a member of the flavonol class of flavonoids having anti-inflammatory and anti-oxidative potential. Previously we reported the inhibitory effect of galangin on the mast cell-mediated allergic inflammation. For incremental research, we investigated the effects of galangin on atopic dermatitis (AD)-like skin lesions and underlying mechanisms of action. We established an atopic dermatitis model in BALB/c mice by repeated local exposure of house dust mite (Dermatophagoides farinae) extract (DFE) and 2,4-dinitrochlorobenzene (DNCB) to the ears. Repeated alternative treatment of DFE/DNCB caused AD-like skin lesions. Topical application of galangin reduced AD symptoms based on ear thickness and histopathological analysis, in addition to serum IgE and IgG2a levels. Galangin inhibited mast cell infiltration into the ear and serum histamine level. Galangin suppressed DFE/DNCB-induced expression of interleukin (IL)-4, IL-5, IL-13, IL-31, IL-32, and interferon (IFN)-γ in the ear tissue. To define the underlying mechanisms of action, tumor necrosis factor-α/IFN-γ-activated human keratinocytes (HaCaT) model was used. Galangin significantly inhibited the expression of cytokines and chemokine by the down-regulation of nuclear factor-κB and mitogen-activated protein kinases in HaCaT cells. Taken together, the results demonstrate that galangin inhibited AD-like symptoms, suggesting that galangin might be a candidate for the treatment of AD.     

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.     

Oral administration of Astragalus membranaceus inhibits the development of DNFB-induced dermatitis in NC/Nga mice

Epicutaneously administered chemical antigens like 2,4-dinitrofluorobenzene (DNFB), evoke an atopic dermatitis (AD)-like dermatitis reaction in NC/Nga mice under specific pathogen free (SPF) conditions. Astragalus membranaceus (AM), is a popular herbal medicine used to treat allergic diseases in East Asia. In the present study, we examined whether AM suppress AD-like skin lesions in NC/Nga mice treated with DNFB under SPF conditions. Oral administration of AM to DNFB-treated NC/Nga mice was found to inhibit ear thickness increases and the skin lesions induced by DNFB. Moreover, IFN-gamma production by CD4(+) T cells from the lymph nodes of DNFB-treated NC/Nga mice was significantly inhibited by AM treatment, although levels of IL-4 and total IgE in serum were not. Study findings suggest that AM may suppress the development of AD-like dermatitis in DNFB-treated NC/Nga mice by reducing IFN-gamma production.     

The Leaves of Broussonetia kazinoki Siebold Inhibit Atopic Dermatitis-Like Response on Mite Allergen-Treated Nc/Nga Mice

Broussonetia kazinoki Siebold. (B. kazinoki) has long been used in the manufacture of paper in Asian countries. Although B. kazinoki leaves (BK) have been employed in dermatological therapy, use of BK has not been tested in patients with atopic dermatitis (AD). Using Nc/Nga mice, which are genetically predisposed to develop AD-like skin lesions, we confirmed the efficacy of BK in AD treatment. BK extract was applied topically to Dermatophagoides farinae-induced AD-like lesions in Nc/Nga mice, and the effects were assessed both clinically and by measuring skin thickness on the back and ears. We measured the effects of BK extract on plasma levels of IgE and IL-4. We also measured the ability of BK extract to inhibit the secretion of hTARC in HaCaT cells after stimulation by TNF-α and IFN-γ. We found that BK extract significantly reduced ear and dorsal skin thickness and the clinical signs of AD, as well as significantly down-regulating the plasma levels of IgE and IL-4 (p<0.01 for each comparison). Moreover, 500 μg/mL of BK extract inhibited hTARC secretion in HaCaT cells by activated TNF-α/IFN-γ by about 87%. These findings suggest that topical application of BK extract has excellent potential in the treatment of AD.     

Oral administration of royal jelly inhibits the development of atopic dermatitis-like skin lesions in NC/Nga mice

We have shown previously that in addition to IL-4, IL-5 and IL-10, antigen-specific interferon-gamma (IFN-gamma) production by spleen cells from ovalbumin (OVA)/Alum-immunized mice is inhibited by the administration of royal jelly (RJ). Since it has been shown that both Th1 and Th2 cytokines play pathogenic roles in the generation of atopic dermatitis (AD), we have examined whether RJ suppresses the development of AD-like skin lesions in NC/Nga mice induced by repeated application of picryl chloride (PiCl) under specific pathogen-free (SPF) conditions. Oral administration of RJ to the PiCl-treated NC/Nga mice inhibited the development of AD-like skin lesions in these mice as exemplified by the significant decrease in the total skin severity scores and the decrease in hypertrophy, hyperkeratosis, and infiltration of the epidermis and corium by inflammatory cells. IFN-gamma production by spleen cells from PiCl-treated NC/Nga mice in response to TNP-KLH was partially but significantly inhibited by the oral administration of RJ, while IFN-gamma production by Con A-stimulated spleen cells was not affected. Since inducible nitric oxide (NO) synthase (iNOS)-derived NO has been suggested as an important immunoregulatory mediator in inflammatory autoimmune diseases, we have also examined the expression of iNOS in the dorsal skin lesions of PiCl-treated NC/Nga mice. Interestingly, the expression of iNOS was significantly increased in the skin lesions of RJ-administered mice compared with those of control PBS-administered mice. Thus, our results suggest that RJ suppresses the development of AD-like skin lesions in PiCl-treated NC/Nga mice, possibly by a combination of down-regulating TNP-specific IFN-gamma production and up-regulating iNOS expression.     

Topical application of a novel ceramide derivative, K6PC-9, inhibits dust mite extract-induced atopic dermatitis-like skin lesions in NC/Nga mice

Atopic dermatitis (AD) is a chronic inflammatory skin disease. K6PC-9 (N-Ethanol-2-hexyl-3-oxo-decanamide) is a novel synthetic ceramide derivative of PC-9S (N-Ethanol-2-mirystyl-3-oxo-stearamide), which was known to be effective in atopic and psoriatic patients. To investigate the immunomodulatory activity of K6PC-9, we examined the effect of K6PC-9 on T lymphocyte and macrophage function and the effect of topical application of K6PC-9 on skin inflammation and AD-like skin lesions in mouse models. K6PC-9 had no effect on concanavalin A-induced proliferation, interleukin (IL)-2 secretion and IL-4 secretion in mouse splenocytes. In contrast, lipopolysaccharide-induced nitrite generation was potently suppressed by K6PC-9 in mouse peritoneal macrophages. In mouse model of skin inflammation, K6PC-9 inhibited phorbol ester-induced increase in ear thickness and expression of tumor necrosis factor-alpha in the ear of BALB/c mice. Topical application of K6PC-9 also suppressed mite extract-induced AD-like skin lesions in NC/Nga mice. Increase in ear thickness was significantly inhibited by K6PC-9 in this model. K6PC-9 also blocked the infiltration of mast cells and neutrophils into the ear. Further study demonstrated that the mRNA expression of tumor necrosis factor-alpha and adhesion molecules, such as vascular cell adhesion molecule-1, intercellular adhesion molecule-1, E-selectin, was also suppressed by K6PC-9 in the ear of mite extract-treated NC/Nga mice. Taken together, the results presented in this report show that K6PC-9 has an anti-inflammatory potential and exerts beneficial effects in an animal model of AD, indicating that K6PC-9 might be used as a topical agent for the treatment of AD.     

Rosmarinic acid attenuates 2,4-dinitrofluorobenzene-induced atopic dermatitis in NC/Nga mice

Atopic dermatitis (AD) is one of the most common skin diseases, and its incidence is increasing in industrialized countries. Furthermore, the epicutaneous application of a hapten, such as 2,4-dinitrofluorobenzene (DNFB), evokes an AD-like lesion in NC/Nga mice under specific pathogen-free (SPF) conditions. Rosmarinic acid (RA) is a secondary metabolite that is frequently found in herbs, and has anti-inflammatory, anti-oxidant, and anti-microbial effects. In this study, we studied whether RA is an effective treatment against DNFB-induced AD-like skin lesions in NC/Nga mice. RA at 1 or 5 μM was found to suppress the productions of interferon (IFN)-γ and interleukin (IL)-4 significantly by activated CD4(+) T cells. Furthermore, an intraperitoneal injection of RA at 10 or 50 mg/kg significantly inhibited skin lesion development and ear thickness and total serum IgE level increases in DNFB-treated NC/Nga mice. In addition, intraperitoneal administered RA at 10 or 50 mg/kg significantly inhibited the infiltrations of CD4(+) T, CD8(+) T, and mast cells into DNFB-induced skin lesions in NC/Nga mice. This study suggests that RA suppresses the development of AD-like dermatitis in DNFB-treated NC/Nga mice by reducing IFN-γ and IL-4 production by activated T cells and total serum IgE levels.     

Topical application of Pleurotus eryngii extracts inhibits 2,4-dinitrochlorobenzene-induced atopic dermatitis in NC/Nga mice by the regulation of Th1/Th2 balance

Pleurotus eryngii is a nutritional and medicinal food rich in polysaccharides that enhance the host immune system as a response to various diseases. The present study investigated the effects of P. eryngii extracts (PEE) on the progress of atopic dermatitis (AD)-like skin lesions in NC/Nga mice induced by 2,4-dinitrochlorobenzene (DNCB). We evaluated skin dermatitis severity, ear thickness, histopathological examination, and cytokines level in DNCB-applied mice treated with PEE. Continuous treatment of PEE inhibited the development of the AD-like skin lesions. PEE suppressed DNCB-induced dermatitis severity, serum level of IgE and thymus and activation-regulated chemokine (TARC), and mRNA expression of TNF-α, INF-γ, IL-4, IL-5, and IL-13 in mice. In addition, PEE reduced thickness of the dermis and dermal infiltration of inflammatory cells and mast cells in histopathological examination. These results indicate that PEE inhibits allergic contact dermatitis through the modulating of T helper (Th)1 and Th2 responses and diminishing the inflammatory cells and mast cells infiltration in the skin lesions in NC/Nga mice.     

Inhibitory effect of Psidium guajava water extract in the development of 2,4-dinitrochlorobenzene-induced atopic dermatitis in NC/Nga mice

Atopic dermatitis (AD) is a chronic, relapsing, and inflammatory skin disease associated with eczematous symptoms and IgE hyperproduction. Psidium guajava is an important food crop and medicinal plant with anti-oxidant, anti-inflammatory, and anti-allergic activities, supporting its traditional uses. Our previous studies have shown that P. guajava extract inhibits Th2 chemokine expression by suppressing the activation of NF-κB and STAT1 co-stimulated with TNF-α and INF-γ. In this study, we investigated the inhibitory effect of P. guajava water extract (PGW) on 2,4-dinitrochlorobenzene (DNCB)-induced AD-like skin lesions in NC/Nga mice. Treatment of cream containing PGW onto DNCB-induced AD-like skin lesions in NC/Nga mice ameliorated lesion intensity scores, levels of IgE, thymus and activation-regulated chemokine (TARC), TNF-α, and IL-4 in serum and ears. In contrast, PGW increased level of the immunosuppressive cytokine IL-10. Histological analyses demonstrated decreased thickening of the epidermis/dermis as well as dermal infiltration by inflammatory cells. These results suggest that cream containing PGW may be a potential therapeutic modality for AD and adjunctive agent to control pruritus in AD.     

Omega-3 fatty acid-derived mediator,Resolvin E1, ameliorates 2,4-dinitrofluorobenzene-induced atopic dermatitis in NC/Nga mice

Atopic dermatitis (AD) is a common inflammatory skin disease for which few effective treatments are available. Resolvin E1 (RvE1; 5S,12R,18R-trihydroxy-6Z,8E,10E,14Z,16E-eicosapentaenoic acid) is an endogenous lipid mediator derived from omega-3 fatty eicosapentaenoic acid, which is a potent inhibitor of inflammation. AD-like skin lesion was induced by repetitive skin contact with DNFB in NC/Nga mice and the effects of RvE1 were evaluated on the basis of histopathological findings of skin, ear swelling and cytokine production of CD4⁺ T cells. Intraperitoneal injection of RvE1 for one week after DNFB challenge significantly lowered ear swelling and improved back skin lesions. In addition, RvE1 significantly suppressed production of interferon-gamma (IFN-γ) and interleukin-4 (IL-4) by activated CD4⁺ T cells and serum IgE level. Furthermore, RvE1 reduced DNFB-induced infiltration of eosinophils, mast cells, CD4⁺ T cells, and CD8⁺ T cells in skin lesions.Therefore, RvE1 may suppress the development of AD-like skin lesions in DNFB-treated NC/Nga mice by reducing IL-4 and IFN-γ of activated CD4⁺ T cells and serum IgE levels and infiltration of immune cells to skin lesion.     

p38 MAPK Inhibitor NJK14047 Suppresses CDNB-Induced Atopic Dermatitis-Like Symptoms in BALB/c Mice

Atopic dermatitis (AD) is a chronic inflammatory skin disorder. Suppression of MAPKs and NF-κB is implicated as a vital mechanism of action of several traditional Chinese medicines for AD therapy. Although overexpression of MAPK mRNA in the skin tissue has been shown in the AD model, the roles of each MAPK in AD pathogenesis have rarely been studied. This study examined the effect of NJK14047, an inhibitor of p38 MAPKs, on AD-like skin lesions induced in BALB/c mice by sensitization and challenges with 1-chloro-2,4-dinitrobenzene (CDNB) on dorsal skin and ears, respectively. After induction of AD, NJK14047 (2.5 mg/kg) or dexamethasone (10 mg/kg) was administrated for 3 weeks via intraperitoneal injection. Following its administration, NJK14047 suppressed CDNB-induced AD-like symptoms such as skin hypertrophy and suppressed mast cell infiltration into the skin lesions. It also reduced CDNB-induced increase in T_H2 cytokine (IL-13) and T_H1 cytokines (interferon-γ and IL-12A) levels but did not decrease serum IgE level. Furthermore, NJK14047 blocked CDNB-induced lymph node enlargement. These results suggest that NJK14047, a p38 MAPK inhibitor, might be an optimal therapeutic option with unique modes of action for AD treatment.     

Effect of Lactobacillus acidophilus strain L-55 on the development of atopic dermatitis-like skin lesions in NC/Nga mice

In this study, we examined whether Lactobacillus acidophilus strain L-55 (strain L-55) suppresses the development of atopic dermatitis (AD)-like skin lesions induced by repeated application of 2,4,6-trinitrochlorobenzene (TNCB) in sensitized NC/Nga mice. The effect of strain L-55 was assessed by measuring clinical symptoms, ear swelling, scratching behavior and serum levels of total IgE. Strain L-55 was administered orally once a day: Strain L-55 at doses of 1 and 10 mg cells/mouse inhibited the development of AD-like skin lesions in dermatitis scores for the back. The increase of dermatitis score and ear swelling was also inhibited by strain L-55. In addition, strain L-55 also caused an inhibition of histological changes induced by repeated application of TNCB. Scratching behavior observed in the back and ear was inhibited by strain L-55. Furthermore elevated serum IgE levels observed by TNCB were also decreased by strain L-55. These results indicate that the inhibition of strain L-55 on AD-like lesions induced by repeated application of TNCB in sensitized NC/Nga mice occurred via a decrease in the serum total IgE level.     

Oral administration of heat-killed Lactobacillus brevis SBC8803 ameliorates the development of dermatitis and inhibits immunoglobulin E production in atopic dermatitis model NC/Nga mice

We have previously shown that the oral administration of heat-killed Lactobacillus brevis (L. brevis) SBC8803 strain inhibits IgE production in ovalbumin (OVA)-sensitized BALB/c mice through improvement of the type-1 helper T (Th1)/Th2 balance toward Th1 dominance. Atopic dermatitis is one of the most common skin diseases and is frequently associated with elevated immunoglobulin E (IgE) antibodies against many kinds of allergens. In this study, we investigated the inhibitory effect of oral administration of L. brevis SBC8803 on the development of dermatitis and IgE elevation using the NC/Nga atopic dermatitis model mice. Male 8-week-old NC/Nga mice were sensitized by the topical application of picryl chloride to foot pads and shaved abdomen. These mice were boosted with picryl chloride by topical application onto the ears once a week for 9 weeks. The mice (n=10 per group) were fed a diet containing 0%, 0.05% or 0.5% of heat-killed L. brevis SBC8803 from 2 weeks before the first sensitization to the end of the study. Total IgE concentration in serum, clinical score, and ear thickness were periodically examined throughout the study. Finally, cytokine (interleukin (IL)-4, IL-5, IL-6, IL-10, IL-12, IFN-gamma and transforming growth factor (TGF)-beta) productions from splenocytes and Peyer's patch (PP) cells of mice were measured. Oral administration of L. brevis SBC8803 significantly inhibited IgE production and ear swelling, and suppressed the development of dermatitis in a dose-dependent manner. Immunosuppressive cytokines such as IL-10 and TGF-beta production from PP cells significantly increased in the 0.5% group compared to the control group although Th1-type and Th2-type cytokines production was not affected.     

1β-Hydroxyalantolactone,a sesquiterpene lactone from Inula japonica,attenuates atopic dermatitis-like skin lesions induced by 2,4-dinitrochlorobenzene in the mouse

Context: 1β-Hydroxyalantolactone (IJ-5) is a sesquiterpene lactone compound isolated from Inula japonica Thunb (Asteraceae). Sesquiterpene lactones have been shown to modulate many processes that influence inflammatory reactions.

Objective: The present study examines the protective effect of IJ-5 on atopic dermatitis (AD) in a mouse model induced by 2,4-dinitrochlorobenzene (DNCB).

Materials and methods: AD-like skin lesions were induced in Balb/c mice by sensitizing once with painting 100?μL of 5% DNCB on their shaved back skin and then challenging with 20?μL of 0.2% DNCB five times on their right ears at 3?d interval starting on day 5 post-sensitization. IJ-5 was administrated intraperitoneally at 10?mg/kg 1?h before each DNCB challenge.

Results: IJ-5 treatment attenuated DNCB-induced dermatitis severity and right ear swelling. The serum levels of IgE, IL-4, and IL-6 in IJ-5-treated mice were reduced by 54.7, 56.5, and 53.0%, respectively, while the mRNA levels of TNFα, IL-1, IL-4, and IL-6 in back skin lesions of IJ-5-treated mice were reduced by 47.7, 61.5, 57.5, and 58.5%, respectively, compared with untreated controls. Histopathological examination showed that IJ-5 treatment decreased DNCB-induced hypertrophy, hyperkeratosis, and infiltration of inflammatory cells in both ear and back skins. Moreover, IJ-5 suppressed the expression of TNFα, IL-1, and IL-6 with IC₅₀ values of 6.58, 9.48, and 7.01?μM, respectively, and inhibited the activation of NF-κB pathway in TNFα-stimulated HaCat cells.

Discussion and conclusion: The present study demonstrates the protective effects of IJ-5 against AD-like skin inflammation and highlights IJ-5 as a potential therapeutic agent for AD.     

Comparison of anti-atopic dermatitis activities between DHMEQ and tacrolimus ointments in mouse model without stratum corneum

This study is aimed to further investigate the anti-atopic dermatitis (AD) activities of dehydroxymethylepoxyquinomicin (DHMEQ) ointment and compare its effect with that of tacrolimus ointment based on the previous study that DHMEQ improves AD-like lesions. AD were induced by 2,4-dinitroclilorobenzene/oxazolone (DNCB/OX) repeatedly on the ears of BABL/C mice while medical tape was additionally used to disrupt stratum corneum in order to exacerbate the lesions. The mice were randomly divided into groups, which are normal, vehicle, DHMEQ (0.1%) and tacrolimus (0.1%). Those in the last two groups were externally applied with DHMEQ ointment and tacrolimus ointment, respectively. The results showed that both of them significantly improved dermatitis symptoms of DNCB/OX-induced AD-like lesions, such as redness, itching, weeping, scaling and thickening of the skin, while reducing epidermis thickness, dermis thickness and the number of mast cells as well, which were examined histopathologically. In contrast with DHMEQ, tacrolimus led to a significant decrease in body weight after long-term application. Both DHMEQ and tacrolimus suppress DNCB-induced increase of serum total IgE and attenuate expression of inflammatory factors IL-4, IL-6, IL-13, IL-1β and interferon (IFN)-γ in the disrupted ear tissues. On the other hand, the mice applied with tacrolimus became obviously irritable, jumping up and down, and inflammatory exudation on the lesioned-skin surface of the mice was remarkably observed. Contrary to the side effects made by tacrolimus, DHMEQ didn't cause any adverse stimulus response. As a conclusion, DHMEQ is safer, milder and more suitable for long-term use than tacrolimus for the treatment of AD-like lesions.     

Immunosuppressive effects of fisetin against dinitrofluorobenzene-induced atopic dermatitis-like symptoms in NC/Nga mice

Atopic dermatitis (AD) is a multifactorial chronic skin disorder that is increasing in prevalence globally. In NC/Nga mice, repetitive epicutaneous applications of 2-4-dinitrofluorobenzene (DNFB) induces AD-like clinical symptoms. Bioflanonol fisetin (3,7,3′,4′-tetrahydroxyflavone) is a dietary component found in plants, fruits and vegetables. Fisetin has various physiological effects that include anti-oxidation, anti-angiogenesis, anti-carcinogenesis and anti-inflammation. In this study, we investigated whether fisetin relieves AD-like clinical symptoms induced by repeated DNFB treatment in NC/Nga mice. Fisetin significantly inhibited infiltration of inflammatory cells including eosinophils, mast cells and CD4⁺ T and CD8⁺ T cells, and suppressed the expressions of cytokines and chemokines associated with dermal infiltrates in AD-like skin lesions. Total serum immunoglobulin E (IgE) levels and the ratio of phospho-NF-κB p65 to total NF-κB p65 were markedly reduced by fisetin. Fisetin also reduced the production of interferon-gamma and interleukin-4 by activated CD4⁺ T cells in a dose-dependent manner, whereas the anti-inflammatory cytokine, interleukin-10 was increased. These results implicate fisetin as a potential therapeutic for AD.