Sophoricoside from Styphnolobium japonicum improves experimental atopic dermatitis in mice.

BACKGROUND: Abnormal immune responses, specifically excessive differentiation of Th2 cells, are associated with the development of atopic dermatitis (AD). Sophoricoside, the genistein-4'-ß-D-glucoside isolated from Styphnolobium japonicum, has previously demonstrated anti-inflammatory and immunosuppressive effects along with IL-3 and IL-5 inhibitory activities. Therefore, we speculated that sophoricoside could regulate AD by regulating abnormal immune responses. PURPOSE: To investigate the role of sophoricoside on AD-like allergic skin inflammation induced by ovalbumin (OVA) or 2,4,6-trinitrochlorobenzene (TNCB) in mouse models. METHODS: Sophoricoside was isolated from the 70% ethanol extract of S. japonicum dried mature seeds. After being submitted to a purification process, its purity was assessed by high-performance liquid chromatography (HPLC). The effects of sophoricoside were determined in vivo by OVA- and TNCB-induced AD-like allergic skin inflammation in mice. Skin tissues were subjected with hematoxylin-eosin (H&E), Giemsa and toluidine blue staining. In vitro CD4+ T cell differentiation was performed and the levels of serum immunoglobulins, cytokines, and genes related to CD4+ T cell differentiation were determined by enzyme-linked immunosorbent assay (ELISA) and quantitative real-time PCR. Cytokine bioassay, mixed lymphocytes reaction and cell viability assay were performed. RESULTS: Topical application of sophoricoside decreased the symptoms of AD-like allergic skin inflammation, including elevated hypertrophic scars with spongiotic epidermis, epidermal hyperplasia, hyperkeratosis, infiltration of immune, and mast cells, dermal thickness, amounts of immunoglobulins, and pro-inflammatory cytokines, and the mast cell population in the skin. Sophoricoside also decreased T cell antigen receptor (TCR)-mediated immune responses. In particular, sophoricoside suppressed the differentiation of naïve CD4+ T cells into Th cell subsets, including Th1, Th2, and Th17, by inhibiting the expression of their subset-specific master transcription factors, leading to suppression of the expression and production of these cell subset-specific cytokines. CONCLUSION: Sophoricoside can improve AD-like allergic skin diseases mainly by inhibiting pathogenic CD4+ T cell differentiation and immune responses.

Therapeutic Effects of Korean Red Ginseng Extract in a Murine Model of Atopic Dermatitis: Anti-pruritic and Anti-inflammatory Mechanism.

Korean red ginseng (KRG) and ginsenosides exhibit diverse biological effects, including anti-inflammatory and anti-allergic. We aimed to investigate the therapeutic effect of KRG in a murine model of atopic dermatitis (AD) is mediated whether by diminishing the pruritus or by suppressing the inflammation. Thirty NC/Nga mice were randomly divided to 5 groups. AD-like skin lesions were induced by percutaneous challenge with 2,4,6-trinitro-1-chrolobenzene (TNCB) on the ears and backs of NC/Nga mice. KRG extract, evening primrose oil, cyclosporine, and phosphate-buffered saline were administered orally by a gastric tube. Each study group was also divided into scratching-permitted and scratching-restricted subgroups to evaluate the impact of scratching behavior on AD. The effects of KRG and the other agents were assessed by measuring the clinical severity score, ear thickness, extent of transepidermal water loss (TEWL), number of scratching movements, total systemic immunoglobulin E (IgE) and interleukin (IL)-31 levels, histologic changes of cutaneous lesions, and mRNA expression levels of tumor necrosis factor (TNF)-α, interferon (IFN)-γ, thymic stromal lymphopoietin (TSLP), and IL-31. KRG exerts therapeutic effects against AD by inhibiting the T helper 2 (Th2) mediated inflammation as well as by diminishing the itching sensation. Moreover, restricting scratching behavior suppresses the vicious cycle of itching and scratching, thus reducing clinical and systemic inflammation in our murine model of AD.

Ultraviolet Radiation-Induced Immunosuppression: Induction of Regulatory T Cells.

Solar/ultraviolet (UV) radiation exerts a variety of biological effects, including suppression of the immune system. UV-induced immunosuppression is induced by suberythemogenic/physiological UV doses, and it affects primarily T-cell driven immune reactions. Another characteristic feature of UV-induced immunosuppression is its antigen-specificity. This is due to the induction of T cells with suppressive features, called regulatory T cells. Since UV-induced regulatory T cells may harbor therapeutic potential phenotypic and functional characterization of these cells is ongoing. Most of these studies have been performed in the murine model of contact hypersensitivity. In this protocol we describe a method for the UV-induced suppression of the induction of contact hypersensitivity and the adoptive transfer of immune response.

[Effects of Blending Oil of Lavender and Thyme on Oxidative Stress, Immunity, and Skin Condition in Atopic Dermatitis Induced Mice].

PURPOSE: The purpose of this study was to evaluate the effects of essential oil on oxidative stress, immunity, and skin condition in atopic dermatitis (AD) induced mice. METHODS: This study was a 3×3 factorial design. Factors were oil type (Lavender, Thyme, and 2:1 mixture of lavender and thyme oil [blending oil]) and treatment period (0 day, 7 days, and 21 days). The samples were 45 mice with AD and randomly assigned to nine groups of five mice per group. The dependent variables such as superoxide radical, IgE, degranulated mast cells, and epidermal thickness were measured. Data were collected from February to April in 2014. Descriptive statistics, One-way ANOVA, Two-way ANOVA, and Tukey's HSD test were performed using the SPSS WIN 20.0 program. RESULTS: Dependent variables were not statistically significantly different by the three oil types (p>.05). Essential oils such as lavender, thyme, and blending oil were all effective in reducing AD symptoms and especially 2:1 blending oil were most effective. There were statistically significant differences by the three treatment periods in all dependent variables (p<.001). There were statistically significant interactions between oil types and treatment periods in all dependent variables (p<.01). For decreasing superoxide radical, degranulated mast cells, and epidermal thickness, 2:1 mixed oil should be applied for at least 21 days. Otherwise to reduce IgE, 2:1 mixed oil should be used for at least 7 days. CONCLUSION: These findings provide bases for developing effective interventions for AD patients to manage their AD symptoms.

Fibroblasts support migration of monocyte-derived dendritic cells by secretion of PGE2 and MMP-1.

The outcome of a cutaneous immune response is critically dependent upon the ability of dendritic cells (DC) to migrate from skin to the draining lymph nodes - a process that is influenced by the cutaneous tissue microenvironment. Here, the role of fibroblasts - a major component of the dermal microenvironment - on the migratory capacity of monocyte-derived DC (MoDC) was investigated in a 3D collagen I matrix. Indeed, dermal fibroblasts supported the migration of pre-activated MoDC through a 3D collagen I matrix. Activation of human MoDC resulted in the release of TNFα and IL-1ß that in turn stimulated MMP-1 (human collagenase) and PGE2 secretion by human dermal fibroblasts. Transmigration assays confirmed the importance of fibroblast-derived MMP-1 and PGE2 for the migration of MoDC through a 3D collagen I matrix. Finally, in mice initiation of inflammation by induction of an irritant contact dermatitis or a psoriasis-like skin inflammation, the expression of the PGE2 generating cox-2 and the mouse collagen I degrading enzyme matrix metalloproteinases (MMP)-13 was strongly up-regulated. Our study indicates that MoDC are able to instruct dermal fibroblasts resulting in enhanced migratory capability of MoDC, thus highlighting the role of a crosstalk of DC with their stromal microenvironment for the control of cutaneous immune responses.

Histamine suppresses regulatory T cells mediated by TGF-ß in murine chronic allergic contact dermatitis.

Regulatory T cells (Tregs) suppress effector T cells and ameliorate contact hypersensitivity (CH); however, the role of Tregs in chronic allergic contact dermatitis (CACD) has not been assessed. Repeated elicitation of CH has been used to produce CACD models in mice. We previously showed that the presence of histamine facilitates the creation of eczematous lesions in this model using histidine decarboxylase (HDC) (-/-) mice. Therefore, the effects of histamine on Tregs in the CACD model were investigated in this study. CACD was developed by repeated epicutaneous application of 2, 4, 6-trinitro-1-chlorobenzene (TNCB) on HDC (+/+) and HDC (-/-) murine skin to assess the effects of histamine in CACD. Histamine aggravated CACD in the murine model and suppressed the number of Tregs in the skin. Histamine also suppressed the level of TGF-ß1 in this model. Recombinant TGF-ß1 or anti-TGF-ß1 antibody was injected into the dorsal dermis of HDC (+/+) mice daily just before TNCB challenge to determine the effects of histamine-regulated TGF-ß on the Treg population in CACD. Recombinant TGF-ß1 injection promoted the infiltration of Tregs in the skin and the production of IL-10; however, anti-TGF-ß1 antibody injection suppressed the number of Tregs in the skin and the production of IL-10. Histamine suppresses the number of Tregs in CACD, and this effect is mediated by TGF-ß.

Effects of Blending Oil of Lavender and Thyme on Oxidative Stress, Immunity, and Skin Condition in Atopic Dermatitis Induced Mice

PURPOSE: The purpose of this study was to evaluate the effects of essential oil on oxidative stress, immunity, and skin condition in atopic dermatitis (AD) induced mice. METHODS: This study was a 3x3 factorial design. Factors were oil type (Lavender, Thyme, and 2:1 mixture of lavender and thyme oil [blending oil]) and treatment period (0 day, 7 days, and 21 days). The samples were 45 mice with AD and randomly assigned to nine groups of five mice per group. The dependent variables such as superoxide radical, IgE, degranulated mast cells, and epidermal thickness were measured. Data were collected from February to April in 2014. Descriptive statistics, One-way ANOVA, Two-way ANOVA, and Tukey's HSD test were performed using the SPSS WIN 20.0 program. RESULTS: Dependent variables were not statistically significantly different by the three oil types (p >.05). Essential oils such as lavender, thyme, and blending oil were all effective in reducing AD symptoms and especially 2:1 blending oil were most effective. There were statistically significant differences by the three treatment periods in all dependent variables (p <.001). There were statistically significant interactions between oil types and treatment periods in all dependent variables (p <.01). For decreasing superoxide radical, degranulated mast cells, and epidermal thickness, 2:1 mixed oil should be applied for at least 21 days. Otherwise to reduce IgE, 2:1 mixed oil should be used for at least 7 days. CONCLUSION: These findings provide bases for developing effective interventions for AD patients to manage their AD symptoms.

Close relationship between T helper (Th)17 and Th2 response in murine allergic contact dermatitis.

BACKGROUND: Repeated exposure to allergens induces chronic allergic lesions in the skin and a shift in the cutaneous cytokine milieu to T helper (Th)2. AIM: To assess the relationships between Th17 and Th2 response during allergic contact dermatitis (ACD) in mice. METHODS: ACD was induced in C57BL/6 mice by single or repeated epicutaneous challenge of 2,4,6-trinitro-1-chlorobenzene. Relationships between Th17 and Th2 response were analyzed by immunohistochemical observations and activity of cytokines on days 8 (first challenge), 18 (11th challenge), 28 (21st challenge) and 38 (31st challenge). RESULTS: On day 8, tissue levels of interleukin (IL)-17 and IL-22 were high, whereas tissue levels of IL-4 and serum IgE concentration were low. Following acute contact dermatitis, mice developed chronic eczematous lesions on day 18, and gradually improved on days 28 and 38. Tissue IL-4 and serum IgE levels corresponded to the development and improvement of chronic eczematous lesions. Numbers of Th17 cells and tissue levels of IL-17 and IL-22 rapidly decreased as IL-4 and IgE levels increased on day 18. As levels of IL-4 and IgE decreased, the number of Th17 cells and tissue levels of IL-17 and IL-22 increased again on days 28 and 38. On day 18, tissue levels of Th17 response-inducing cytokines (IL-6, IL-23 and transforming growth factor-ß) were high, and IL-23-expressing cells appeared in abundance, when Th2 response was extremely high. IL-17 injection decreased tissue IL-4 and serum IgE levels. CONCLUSIONS: Th17 correlates closely with Th2 in murine chronic ACD induced by repeated epicutaneous challenge.

Activation of cell-mediated immunity by Morinda citrifolia fruit extract and its constituents.

Morinda citrifolia, commonly known as noni, is a traditional natural medicine in French Polynesia and Hawaii. Functional foods derived from M. citrifolia fruit have been marketed to help prevent diseases and promote good health. The objective of this study was to assess the effects of M. citrifolia fruit on cell-mediated immunity. In the picryl chloride-induced contact dermatitis test, M. citrifolia fruit extract (Noni-ext) inhibited the suppression of cell-mediated immunity by immunosuppressive substances isolated from freeze-dried ascites of Ehrlich carcinoma-bearing mice (EC-sup). In addition, Noni-ext inhibited reduction of IL-2 production in EC-sup-treated mice and activated natural killer cells in normal mice. These results suggest that Noni-ext has multiple effects on the recovery of cell-mediated immunity. Furthermore, we investigated the active principles of Noni-ext and identified an iridoid glycoside, deacetylasperulosidic acid. Oral administration of deacetylasperulosidic acid inhibited the reduction of ear swelling, and also cancelled the suppression of IL-2 production along with the activation of natural killer cells in the same manner as that of Noni-ext.

Increased expression of cell adhesion molecule 1 by mast cells as a cause of enhanced nerve-mast cell interaction in a hapten-induced mouse model of atopic dermatitis.

BACKGROUND: Neuroimmunological disorders are involved in the pathogenesis of atopic dermatitis (AD), partly through enhanced sensory nerve-skin mast cell interaction. Cell adhesion molecule 1 (CADM1) is a mast-cell adhesion molecule that mediates the adhesion to, and communication with, sympathetic nerves. OBJECTIVES: To investigate the role of mast cell CADM1 in the pathogenesis of AD, CADM1 expression levels by comparing between lesional and nonlesional skin mast cells of an AD mouse model, which was developed by repeated application of trinitrochlorobenzene, and to examine, in cocultures, how the alterations in CADM1 detected in lesional mast cells might affect the sensory nerve-mast cell interaction. METHODS: AD-like lesional and nonlesional skin mast cells were collected separately by laser capture microdissection. CADM1 expression was examined by reverse transcription-polymerase chain reaction and CADM1 immunohistochemistry. In cocultures, adhesion between dorsal root ganglion (DRG) neurites and IC2 mast cells was analysed by loading a femtosecond laser-induced impulsive force on neurite-attendant IC2 cells, while cellular communication was monitored as the IC2 cellular response ([Ca(2+)]i increase) after nerve-specific stimulant-induced DRG activation. RESULTS: AD-like lesional mast cells expressed three-fold more CADM1 transcripts than nonlesional cells. This was supported at the protein level, shown by immunohistochemistry. In coculture, CADM1 overexpression in IC2 cells strengthened DRG neurite-IC2 cell adhesion and doubled the population of IC2 cells responding to DRG activation. A function-blocking anti-CADM1 antibody abolished these effects in a dose-dependent manner. CONCLUSIONS: Increased expression of CADM1 in mast cells appeared to be a cause of enhanced sensory nerve-mast cell interaction in a hapten-induced mouse model of AD.

Characterization and anti-allergic effect of a polysaccharide from the flower buds of Lonicera japonica.

A water-soluble polysaccharide (LJP-1), with a molecular weight of 1.8×10(5) Da, was isolated from the flower buds of Lonicera japonica. Gas chromatography (GC) analysis showed that the LJP-1 was mainly composed of d-glucose and a small amount of d-arabinose. On the basis of methylation analysis, LJP-1 had the backbone chain mainly consisting of 1,6-linked Glc and 1,3,6-linked Glc, which was terminated with 1-linked Ara residues at the O-3 position of 1,3,6-linked Glc in a relative molar ratio of 2.9:1:0.9. The anti-allergic effect of LJP-1 was evaluated on allergic contact dermatitis (ACD) induced by picryl chloride (PC) in mouse ear. Similar to prednisolone, orally administrated LJP-1 (20, 40 and 80 mg/kg) potently inhibited the PC-induced ACD, leading to substantial reductions in ear thickness, serum level of IgE and histamine, as well as tissue TNF-α. These results demonstrate that treatment with LJP-1 may be effective for preventing the development of PC-induced ACD.

Inhibitory effect of antidepressant drugs on contact hypersensitivity reaction.

BACKGROUND: Contact hypersensitivity (CS) reaction in the skin is T-cell mediated immune reaction which plays a major role in the pathogenesis and chronicity of various inflammatory skin disorders and, like other delayed-type hypersensitivity (DTH) reactions, affords immunity against tumor cells and microbes. CS response is a self-limiting reaction, and interleukin (IL)-10 is considered to be a natural suppressant of cutaneous inflammatory response. Recently, it has been demonstrated that major depression is related to activation of the inflammatory response and elevation of some parameters of cell-mediated immunity. It has been suggested that such activation of the immune system may play a role in etiology of depression. If this immunoactivation is involved in etiology of depression, one would expect that antidepressant agents may have negative immunoregulatory effects. To the best of our knowledge, the effect of antidepressants on contact hypersensitivity has not been studied. METHODS: The aim of the present study was to establish the effect of prolonged desipramine or fluoxetine treatment on CS reaction to picryl chloride. RESULTS: Antidepressants significantly suppressed CS reaction, fluoxetine by 53% whereas desipramine by 47% compared to positive control. Moreover, desipramine and fluoxetine decreased relative weight of auxillary lymph nodes. Desipramine decreased also relative weight of inguinal lymph nodes and spleens whereas desipramine and fluoxetine increased production of IL-10 in comparison to positive control. CONCLUSION: The observed effect of antidepressant drugs on CS reaction is consistent with the hypothesis that T-cell mediated immunity is targeted by antidepressants.

Effect of pedunculagin investigated by non-invasive evaluation on atopic-like dermatitis in NC/Nga mice.

BACKGROUND/PURPOSE: Atopic dermatitis (AD) is a chronic relapsing inflammatory skin disorder that is becoming increasingly prevalent. Experimental animal models have been an indispensable tool for studying its pathological mechanisms and for in vivo testing of novel therapeutic approaches. AD-like lesions can be induced experimentally in NC/Nga mice. Pedunculagin, an ellagitannin purified from the Manchurian alder, Alnus hirsuta var. microphylla, Betulaceae, is a novel immunomodulator. To evaluate the effect of pedunculagin for AD-like lesions in NC/Nga mice, using clinical and non-invasive methods. METHODS: AD-like lesions were induced in NC/Nga mice using 2,4,6-trinitrochlorobenzene (TNCB). A cream containing 0.1% or 0.5% pedunculagin was applied to the positive treatment group, and the base cream without pedunculagin was applied to the negative treatment group. The control group did not receive any kind of topical agents. We evaluated the therapeutic efficacy of pedunculagin for AD by statistical evaluation of the clinical severity score using non-invasive biomedical engineering tools before treatment, and 1 day, 3 days, 1 week, 2 weeks and 4 weeks afterwards. RESULTS: An AD-like skin rash was successfully induced using TNCB in NC/Nga mice. The group receiving higher concentrations of pedunculagin showed faster and greater improvement. CONCLUSION: Our results suggest that remedies made from natural materials like pedunculagin are now showing promise for medical applications, and many new studies are expected to explore this potential.

Effects of the novel and potent lymphocyte-specific protein tyrosine kinase inhibitor TKM0150 on mixed lymphocyte reaction and contact hypersensitivity in mice.

Lymphocyte-specific protein tyrosine kinase (Lck) plays a critical role in T cell activation. In the present study, the effect of a newly synthesized small molecule compound, 7-[2-(dimethylamino)ethoxy]-2-(4-phenoxyphenyl)-9,10-dihydro-4H- pyrazolo[5,1-b] [1,3]benzodiazepine-3-carboxamide (TKM0150) on Lck activity was investigated. TKM0150 inhibited Lck with an 1C50 value of 0.7 nM. To evaluate if TKM0150 is a specific inhibitor of Lck, the activity against several Src (Proto-oncogene tyrosine-protein kinase Src) and non-Src family kinases were assayed. TKM150 inhibited Src family kinases, Src and Csk (c-Src kinase) (with IC50 values of 0.6 nM and 1.7 nM, respectively) as well as Fyn (p59-Fyn) and Lyn (tyrosine-protein kinase Lyn) at a dose of 1 microM; however, it did not inhibit kinase which is a non-Src family kinase in the tyrosine kinase (TK) group, nor kinases in other groups. Then, the anti-inflammtory potential of TKM0150 was evaluated by known experimental models. TKM0150 inhibited the murine mixed lymphocyte reaction (MLR) in vitro with an IC50 value of 0.7 nM, and 2,4,6-trinitro-1-chlorobenzene-induced contact hypersensitivity in vivo at a dose of 0.3 and 1% w/v administered topically. These results indicate that TKM0150 is a specific inhibitor of Lck/Src kinase and can block T cell-mediated responses in vitro and in vivo. Accordingly, TKM0150 would be expected as a drug candidate for treating T cell-mediated disorders including atopic dermatitis.

JNK pathway is required for TNCB-induced IL-18 expression in murine keratinocytes.

The epidermal tissue of the skin is the first line of defense against exposure to microbial, chemical, and physical agents that cause cutaneous immune responses. Epidermal epithelial cells (keratinocytes) produce pro-inflammatory cytokine interleukin-18 (IL-18) potentially relevant for the skin immune responses. Expression of IL-18 was investigated after exposure of murine keratinocytes PAM212 to pro-inflammatory stimuli, allergen TNCB (Trinitrichlorobenzen), LPS (lipopolysaccharide) or PMA (phorbol myristate acetate). IL-18 mRNA transcription and IL-18 secretion were detected by real time-PCR and ELISA, respectively. The results showed that TNCB-induced IL-18 expression in cultured murine keratinocytes in a dose-dependent manner, and it significantly stimulated IL-18 mRNA and protein expression at 10 microM. In addition, both LPS and PMA could increase the expression of IL-18 in murine keratinocytes. To determine the molecular mechanism involved, keratinocytes were pretreated with JNK, p38 or ERK MAPK inhibitors SP600125, SB203580, PD98059. We found that JNK inhibitors could significantly suppress IL-18 expression enhanced by TNCB. Western blot results showed that TNCB could induce the phosphorylation of JNK, but not p38 or ERK1/2. These results suggest that TNCB has an up-regulation effect on IL-18 production in murine keratinocyte cell line PAM212, and that the activation of the JNK signal pathway is the mechanism responsible for TNCB-induced IL-18 gene expression in murine keratinocytes.

Histamine H(4) receptor antagonist ameliorates chronic allergic contact dermatitis induced by repeated challenge.

BACKGROUND: The present study observed effects of the histamine H(4) receptor on chronic allergic contact dermatitis induced by repeated challenge in mice. METHODS: Acute contact dermatitis was induced by single epicutaneous challenge of 2,4,6-trinitro-1-chlorobenzene (TNCB) to the ear. Chronic allergic contact dermatitis was developed by repeated epicutaneous challenge using TNCB on the dorsal back skin. H(4) receptor antagonist JNJ7777120 was administered to wild-type mice, while H(4) receptor agonist 4-methylhistamine was administered to histidine decarboxylase (HDC) (-/-) mice that synthesized no histamine. RESULTS: HDC (-/-) mice did not differ phenotypically from HDC (+/+) mice, and H(4) receptor antagonist/agonist did not have clinical effects in terms of acute contact dermatitis reactions. H(4) receptor antagonist ameliorated skin eczematous lesions induced by repeated TNCB challenge in HDC (+/+) mice. On the contrary, H(4) receptor agonist exacerbated skin lesions exclusively in HDC (-/-) mice. Application of H(4) receptor agonist induced migration of mast cells and eosinophils in skin lesions, and H(4) receptor antagonist suppressed these changes. H(4) receptor was immunohistochemically detected on mast cells in eczematous lesions. Levels of interleukin (IL)-4, -5, and -6 in lesions were decreased, whereas levels of interferon-gamma and IL-12 were increased by H(4) receptor antagonistic activity. Serum Immunoglobulin E levels rapidly increased with repeated challenge, but decreased with H(4) receptor antagonist. CONCLUSION: Because chronic allergic contact dermatitis is developed by H(4) receptor stimulation, H(4) receptor antagonists might represent new candidate drugs for treating chronic allergic contact dermatitis.

Antiallergic activity of unripe Citrus hassaku fruits extract and its flavanone glycosides on chemical substance-induced dermatitis in mice.

Oral administration of a 50% ethanolic extract (CH-ext) obtained from unripe Citrus hassaku fruits collected in July exhibited a potent dose-dependent inhibition of IgE (immunoglobulin E)-mediated triphasic cutaneous reaction at 1 h [immediate phase response (IPR)], 24 h [late phase response (LPR)] and 8 days [very late phase response (vLPR)] after dinitrofluorobenzene challenge in mice. Naringin, a major flavanone glycoside component of CH-ext, showed a potent dose-dependent inhibition against IPR, LPR and vLPR. Neohesperidin, another major glycoside component of CH-ext, showed an inhibition against vLPR. The effect of CH-ext on type IV allergic reaction was examined by determining inhibitory activity against ear swelling in mice by using the picryl chloride-induced contact dermatitis (PC-CD) model. Oral administration (p.o.) of CH-ext and subcutaneous administration (s.c.) of prednisolone inhibited ear swelling during the induction phase of PC-CD. The inhibitory activities of combinations of CH-ext (p.o.) and prednisolone (s.c.) against PC-CD in mice were more potent than those of CH-ext alone and prednisolone alone, without enhancing the adverse effects. Other combinations of prednisolone (s.c.) and flavanone glycoside (p.o.) components of CH-ext, i.e. naringin and neohesperidin, exerted similar synergistic effects.

TCDD exposure exacerbates atopic dermatitis-related inflammation in NC/Nga mice.

Our previous study showed that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure of NC/Nga mice, a mouse model of atopic dermatitis, induces no dermal changes. In the present study, to investigate whether TCDD exacerbates atopic dermatitis-like skin lesions elicited in NC/Nga mice, NC/Nga mice were applied with picryl chloride (PC), and then were exposed to a single oral dose of 0 (control), 5, and 20 microg TCDD/kg. Two weeks later, spleens, blood, and skin specimens were collected. TCDD exposure increased the production of Th1-type cytokine IFN-gamma, but not Th2-type cytokine IL-4, from spleen cells stimulated with a mitogen. The plasma total IgE antibody levels of the TCDD-exposed mice remained at control levels. On the other hand, TCDD exposure markedly increased the mast cell infiltration and degranulation in PC-sensitized NC/Nga mice histologically, as compared with control mice. These results suggest that TCDD exposure exacerbates atopic dermatitis-related inflammation with no increase of IgE antibody production and that TCDD may be one of the environmental pollutants that induce exacerbations of atopic diseases.