Increase In Ear Thickness Research Articles

Toxicological Evaluation and Anti-Inflammatory Activity of a Golden Gelatinous Sorghum Bran Extract

Golden gelatinous sorghum (GGS) is rich in phytochemicals and anti-oxidants. We investigated the toxicity and anti-inflammatory properties of a GGS extract. We observed no toxic effects after a daily dose of up to 5000 mg/kg body weight of the GGS extract administered orally to rats for 14 d. The exposure of mice ears to 12-O-tetradecanoylphorbol-13-acetate (TPA) caused a marked increase in ear thickness, which was significantly inhibited by treating with the GGS extract; this inhibition of inflammatory response was clearly confirmed by a histological analysis. The TPA-induced mice ear edema model, indicated that treating with the GGS extract inhibited the expression levels of such inflammatory mediators as cyclooxygenase-2 and inducible nitric oxide synthase. The nitric oxide level in lipopolysaccharide (LPS)-induced Raw264.7 cells in vitro was lower in the GGS extract-treated group than in the LPS-only treated group. These results suggest that sorghum would be a safe, nontoxic product, and that the GGS extract possessed significant anti-inflammatory activity.

Allergic Skin Inflammation Induced by Chemical Sensitizers Is Controlled by the Transcription Factor Nrf2

Allergic contact dermatitis (ACD) is induced by low-molecular weight electrophilic chemicals and metal ions. Chemical contact sensitizers trigger reactive oxygen species production and provoke electrophilic stress, leading to the accumulation of the transcription factor nuclear-related factor 2 (Nrf2) in innate immune cell types. The objective of this work was to identify the role of Nrf2 in the regulation of ACD. We used the local lymph node assay (LLNA) and the mouse ear swelling test (MEST) to study the role of Nrf2 in both the sensitization and elicitation phase in nrf2 knockout (nrf2(-/-)) and wild-type (nrf2(+/+)) mice. Five chemicals were used: two compounds known to react with cysteine residues, 2,4-dinitrochlorobenzene (DNCB) and cinnamaldehyde (CinA); one sensitizer known to exhibit mixed reactivity to cysteine and lysine residues, isophorone diisocyanate; and one reacting specifically with lysine residues, trimellitic anhydride and croton oil, a well-known irritant. In the MEST assay, DNCB (1 and 2%) induced a significant increase in ear thickness in nrf2(-/-) compared with nrf2(+/+) mice, suggesting a role for Nrf2 in the control of the inflammatory process. When DNCB was used at 0.25 and 0.5% or when mice were treated with CinA, inflammation was found only in nrf2(-/-) mice. In the LLNA, all chemical sensitizers induced an increase of lymphocyte proliferation in nrf2(-/-) compared with nrf2(+/+) mice for the same chemical concentration. These results reveal an important role for Nrf2 in controlling ACD and lymphocyte proliferation in response to sensitizers.

Tumor necrosis factor-α, monocyte chemoattractant protein-1 and intercellular adhesion molecule-1 increase during the development of a 2,4-dinitrofluorobenzene-induced immediate-type dermatitis in rats

Due to the steadily increasing incidence of atopic dermatitis, there is a great medical need for new therapies and improved animal models. To provide more detailed analysis of a Sprague-Dawley rat dermatitis model. Sprague-Dawley rats were actively sensitized by intraperitoneal injections of dinitrophenylated ovalbumin (DNP-OVA) plus alum. Skin reactions were elicited by repeated epicutaneous challenge with 2,4-dinitrofluorobenzene (DNFB). The ear thickness exhibited a significant increase from the first challenge. A relatively steep increase in ear thickness was observed at the fifth DNFB application. After the fifth DNFB application, total serum immunoglobulin (Ig) E and IgG1 levels reached a plateau at 1h compared with the normal group. The peak production of tumor necrosis factor (TNF)-α and monocyte chemoattractant protein (MCP)-1 was found at 1h, while that of intercellular adhesion molecule (ICAM)-1 was found at 24h. Infiltration of CD4+T cells, CD8+T cells, eosinophils and mast cells increased in the skin lesion. The indices such as thickness and inflammatory cell infiltration in the lesional skin were increased by repeated hapten application; TNF-α, MCP-1 and ICAM-1 increased with the development of the dermatitis.

Local and systemic effects of co-stimulatory blockade using cytotoxic T lymphocyte antigen-4-immunoglobulin in dinitrofluorobenzene- and oxazolone-induced contact hypersensitivity in mice

Cytotoxic T lymphocyte-associated antigen-4 (CTLA-4)-immunoglobulin (Ig) has immunosuppressive properties both in vivo and in vitro, but much is still unknown about the mechanisms by which CTLA-4-Ig exerts its immunosuppressive activities in vivo. The aim of this study was to investigate the effect of CTLA-4-Ig in a mouse model of contact hypersensitivity (CHS). The inflammatory response in the presence or absence of CTLA-4-Ig was evaluated by measuring the increase in ear thickness in sensitized animals after challenge. We observed a dose-dependent suppression of the ear swelling in both dinitrofluorobenzene (DNFB)- and oxazolone-induced CHS. The suppressive effect was still present 3 weeks after administration, even in the absence of circulating levels of CTLA-4-Ig. It was further shown that CTLA-4-Ig inhibits activation of T cells in the draining lymph node after sensitization and affects the maturation level of both dendritic cells and B cells. Furthermore, CTLA-4-Ig reduces infiltration of activated CD8(+) T cells into the inflamed ear tissue and suppresses both local and systemic inflammation, as illustrated by reduced expression of cytokines and chemokines in the inflamed ear and a reduced level of acute-phase proteins in circulation. Finally, our results suggest that CTLA-4-Ig has a mainly immunosuppressive effect during the sensitization phase. We conclude that CTLA-4-Ig induces long-term immunosuppression of both DNFB- and oxazolone-induced inflammation and our data are the first to compare the effect of this compound in both DNFB- and oxazolone-induced CHS and to show that CTLA-4-Ig exerts an immunosuppressive effect on both local and systemic inflammatory mediators which is mediated principally during the sensitization phase.

인진호(Artemisia capillaris) 추출물의 항산화 활성 및 알러지성 피부염에 대한 효과

본 연구는 항산화 및 알러지성 피부질환에 대한 효과가 있는 안전성이 확보된 새로운 천연 향장 소재 개발을 위하여 인진호(A. capillaris)를 6종의 용매(<TEX>$dH_2O$</TEX>, ethanol, methanol, acetone, ethyl acetate and hexane)로 추출한 추출물의 항산화 및 항아토피 활성을 검증하였다. 항산화 활성 검증에서는 methanol (DPPH: 85.87%, FRAP: 1.772)과 <TEX>$dH_2O$</TEX> (DPPH: 60.69%, FRAP: 3.185) 등의 극성 용매 추출물에서 우수한 항산화 활성을 나타내었으나 비극성 용매에서는 활성이 거의 없었다(ethyl acetate 41.81%, 0.407, Hexane 8.37%, 0.328). DNFB-induced atopic dermatitis mouse model에 의한 항 아토피에 대한 치유력 측정에서는 인진호 추출물 처리군은 염증 세포의 수에서 음성 대조군과 비교하여 220% 증가로 양성 대조군의 400% 보다 약 45%의 완화 효과를 보여 주었으며, 귀의 두께는 음성 대조군의 175%로 양성 대조군의 330%보다 약 47%가 감소하는 뚜렷한 증상 완화 효과를 나타내었다. 이러한 결과는 인진호 추출물의 항산화 물질이 극성 물질이며, DNFB 처치에 의한 귀의 비후반응 감소와 염증부위의 면역세포 침투현상을 감소시키는 염증반응 완화 기능성 물질을 포함하고 있을 가능성을 알 수 있었다. 이상의 결과를 바탕으로 인진호 추출물에 대한 물리적 특성, 유전자 발현과 면역학적 실험 등이 추가 된다면 새로운 향장소재나 기능성 식품의 소재로도 이용 가능할 것으로 판단된다. The antioxidant activities of 6 solvent extracts of Artemisia capillaris were evaluated in a dintroflurobenzen (DNFB)-induced allergic mouse model. In vitro antioxidant activities were determined using DPPH and the FRAP test. Methanol (DPPH: 85.87%, FRAP: 1.772) and <TEX>$dH_2O$</TEX> (DPPH: 60.69%, FRAP: 3.185) extracts showed the highest antioxidant activities compared with other solvents (ethyl acetate 41.81%, 0.407, hexane 8.37%, 0.328, etc.). In addition, we tested atopic dermatitis (AD)-like skin lesions in mice treated with DNFB. The methanol extract of A. capillaris on the AD-like skin lesions in DNFB-induced atopy inhibited ear thickness increases (47%) and the skin lesions (45%) compared with a positive control (methanol). The results suggest that they have potential as natural antioxidants and allergy-improving substances and that they may be valuable materials in the functional food or cosmeceutical industry.

IMO-8400, a novel TLR7, TLR8 and TLR9 antagonist, inhibits disease development in mouse models of psoriasis (119.8)

Abstract Toll-like receptors (TLR) are involved in the pathogenesis of numerous autoimmune diseases, including psoriasis. The role of TLR7 and TLR9 in psoriasis is well established and TLR8 may also contribute to this disease. Blocking the activation of these receptors through a TLR antagonist represents a novel approach to the treatment of psoriasis. We have developed IMO-8400, a synthetic DNA compound that inhibits TLR7-, TLR8-, and TLR9-mediated immune responses in cell-based assays. Additionally, following subcutaneous administration in non-human primates, it suppresses ex-vivo immune responses mediated through these receptors. IMO-8400 was evaluated in preclinical mouse models of psoriasis, induced by IL-23 cytokine or antimicrobial peptide LL-37. Psoriasis-like skin lesions were induced in the ear of C57BL/6 mice by intradermal injection of IL-23 or LL37. Injected mice were treated with subcutaneous administration of IMO-8400. Mice were euthanized at end of study and tissue samples were taken for histological examination. Increase in ear thickness was inhibited in a dose-dependent manner by treatment with IMO-8400. Reduction in epidermal hyperplasia and infiltrating leukocytes was observed in sample tissues. Treatment with IMO-8400 was associated with elevation of serum IL-10 levels. IMO-8400 can effectively suppress lesion development in these psoriasis models. IMO-8400 has potential as a novel agent for the treatment of psoriasis and other autoimmune diseases.

Anti-Allergic Effects of Vernonia amygdalina Leaf Extracts in Hapten-Induced Atopic Dermatitis-Like Disease in Mice

Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by pruritic and eczematous skin lesions. In this study, AD-like disease was induced in NC/Nga mice so as to evaluate the anti-allergic effects of Vernonia amygdalina leaf extracts (VAM). Forty NC/Nga mice were purchased for each of the two protocols (prophylactic and curative) of the study. Mice were randomly divided in groups of five or six after sensitization with 5% trinitrochlorobenzene (TNCB): aqueous extracts (VAM1), methanolic extracts (VAM2), hydrocortisone (HCT), buffer for the control (TNCB) and the normal mice (NORM) groups. As for HCT, VAM1 and VAM2-pretreated mice showed significantly lower number of scratching behavior episodes (p < 0.01; vs. TNCB) following TNCB challenge. In addition, VAM1, VAM2 exerted a significant inhibitory effect on the development of AD skin symptoms (vs. TNCB group; p < 0.001), the production of IgE, TNF-alpha (p < 0.05), IL-5 and IFN-gamma (p < 0.01) (vs. TNCB group) and on the increase in ear thickness (p < 0.05) in prophylactic protocol. In the AD curative protocol, topical VAM1, VAM2 markedly improved skin lesions such as erythema/hemorrhage (p < 0.05), scaling/dryness, erosion/excoriation (p < 0.01) (vs. TNCB mice). Furthermore, a significant decrease in ear thickness was noted in VAM1, VAM2, HCT groups (vs. TNCB group; p < 0.05) as well as the serum total IgE, MCP-1 (p < 0.01) and eotaxin (p < 0.05). VAM2 also improved chronic eczema dermatitis skin symptoms in a patient. Results from this report suggest that VAM extracts, known as ERK pathway inhibitor, prevent and improve atopic/eczema dermatitis syndrome.

Preclinical Evaluation of Local JAK1 and JAK2 Inhibition in Cutaneous Inflammation

JAKs are required for signaling initiated by several cytokines (e.g., IL-4, IL-12, IL-23, thymic stromal lymphopoietin (TSLP), and IFNγ) implicated in the pathogenesis of inflammatory skin diseases such as psoriasis and atopic dermatitis (AD). Direct antagonism of cytokines, such as IL-12 and IL-23 using ustekinumab, has proven effective in randomized studies in psoriasis patients. We hypothesized that local inhibition of cytokine signaling using topical administration of INCB018424, a small molecule inhibitor of JAK1 and JAK2, would provide benefit similar to systemic cytokine neutralization. In cellular assays, INCB018424 inhibits cytokine-induced JAK/signal transducers and activators of transcription (STAT) signaling and the resultant production of inflammatory proteins (e.g., IL-17, monocyte chemotactic protein-1, and IL-22) in lymphocytes and monocytes, with half-maximal inhibitory concentration values <100 nM. In vivo, topical application of INCB018424 resulted in suppression of STAT3 phosphorylation, edema, lymphocyte infiltration, and keratinocyte proliferation in a murine contact hypersensitivity model and inhibited tissue inflammation induced by either intradermal IL-23 or TSLP. Topical INCB018424 was also well tolerated in a 28-day safety study in Gottingen minipigs. These results suggest that localized JAK1/JAK2 inhibition may be therapeutic in a range of inflammatory skin disorders such as psoriasis and AD. Clinical evaluation of topical INCB018424 is ongoing.

The Immune-Modulating Cytokine and Endogenous Alarmin Interleukin-33 Is Upregulated in Skin Exposed to Inflammatory UVB Radiation

The cellular and molecular mechanisms by which UV radiation modulates inflammation and immunity while simultaneously maintaining skin homeostasis is complex and not completely understood. Similar to the effects of UV, IL-33 has potent immune-modulating properties that are mediated by the downstream induction of cytokines and chemokines. We have discovered that exposure of mice in vivo or human skin samples ex vivo to inflammatory doses of UVB induced IL-33 expression within the epidermal and dermal skin layers. Using a combination of murine cell lines and primary human cells, we demonstrate that both UV and the oxidized lipid platelet activating factor induce IL-33 expression in keratinocytes and dermal fibroblasts. Highlighting the significance of these results, we found that administering IL-33 to mice in vivo suppressed the induction of Th1-mediated contact hypersensitivity responses. This may have consequences for skin cancer growth because UV-induced squamous cell carcinomas that evade immunological destruction were found to express significantly higher levels of IL-33. Finally, we demonstrate that dermal mast cells and skin-infiltrating neutrophils closely associate with UV-induced IL-33-expressing fibroblasts. Our results therefore identify and support a role for IL-33 as an important early danger signal produced in response to inflammation-inducing UV radiation.

The histone deacetylase inhibitor, trichostatin A, inhibits the development of 2,4-dinitrofluorobenzene-induced dermatitis in NC/Nga mice

Repetitive skin contact with a chemical hapten like 2,4-dinitrofluorobenzene (DNFB) evokes an atopic dermatitis (AD)-like dermatitis reaction in NC/Nga mice maintained under specific pathogen-free (SPF) conditions. The histone deacetylase (HDAC) inhibitor, trichostatin A (TSA), modulates the expression of several genes by inhibiting the activity of HDACs. Furthermore, TSA has been reported to suppress inflammatory cytokine expression and to induce T cell-suppression by increasing regulatory T cell (T reg cell) numbers. In addition, histone deacetylase inhibitors (HDACi) are currently undergoing clinical trials for the treatment of inflammatory disorders. In the present study, we examined whether treatment with TSA suppresses AD-like skin lesions in NC/Nga mice treated with DNFB under SPF conditions. Intraperitoneal (i.p.) administration of TSA to DNFB-treated NC/Nga mice was found to inhibit ear thickness increases and the skin lesions induced by DNFB. Furthermore, IL-4 production by CD4 + T cells from the lymph nodes of DNFB-treated NC/Nga mice was significantly inhibited by TSA, although levels of IFN-γ were not. Flow cytometric analysis of lymphocytes showed an increase in CD4 + CD25 + T cell proportions in mice given TSA-i.p. These findings suggest that TSA suppresses the development of AD-like dermatitis in DNFB-treated NC/Nga mice by reducing IL-4 production and increasing the T reg cell population.

Comparative testing for the identification of skin-sensitizing potentials of nonionic sugar lipid surfactants

The Local Lymph Node Assay (LLNA) is the preferred test for the identification of skin-sensitizing potentials of chemicals in Europe and is also the first choice method within REACH. In the formal validation, only a very few surfactant chemicals were evaluated and SDS was identified as a false positive. In this study, 10 nonionic sugar lipid surfactants were tested in an LLNA, guinea pig maximization test (GPMT) and human repeated insult patch test. Of the 10 surfactants tested in the LLNA, 5 showed stimulation indices above 3.0. Three of five positive reactions were concomitant with signs of skin irritation indicated by an increase in ear thickness. In the GPMT, all test products were classified as nonsensitizers. In human volunteers, no skin reactions suggestive of sensitization were reported. In conclusion, these results are indicative of the LLNA overestimating sensitization potentials for this category of chemicals. This may in part be due to irritant effects generated by these surfactants. Until suitable nonanimal alternative tests obtain regulatory acceptance, use of other tests, e.g. GPMTs, may in cases be justified. Results such as these need be taken into account when developing nonanimal alternative methods to ensure reliable data sets for method validation purposes.

Study of the sensitising potential of various textile dyes using a biphasic murine local lymph node assay

Disperse dyes, which are suitable for dyeing synthetic fibres, are responsible for the great majority of allergic contact dermatitis (ACD) cases to textile dyes. The aim of the present study was to investigate the sensitising potential of various disperse dyes using a biphasic protocol of the local lymph node assay (LLNA). Briefly, mice were shaved over a surface of approximately 2 cm(2) on their backs and treated using a "sensitisation-challenge protocol". The shaved surface was treated once daily on days 1-3 with 50 microl of the test solution. Animals remained untreated on days 4-14. On days 15-17, mice were treated with 25 microl of the test solution on the dorsum of both ears. Mice were killed on day 19 with deep CO(2) anaesthesia, the lymph nodes prepared and various end points, such as ear thickness, ear punch weight, lymph node weight, lymph node cell count and the proportion of various lymphocyte subpopulations, were determined by flow cytometry. The results were compared to control group treated with the vehicle alone. Our results showed that almost all of the tested textile dyes caused a significant increase in lymph node cell count and lymph node weight. We also observed an increase in ear thickness and ear punch weight in most of the concentrations tested for various textile dyes. We observed a decrease in CD4+ and CD8+ cells and an increase in CD19+, CD45+ and CD45+/1A+ cells in most of the cases, which is characteristic for allergens. The CD4+/CD69+ cells increased in only few experiments mainly with Disperse Blue 124 and Disperse Blue 106. Based on our results, the disperse dyes could be arranged in four groups on the basis of their sensitising potency in the following decreasing order (in parenthesis: lowest concentration causing a significant increase in lymph node cell number): group 1, strong: Disperse Blue 124 and Disperse Blue 106 (0.003%); group 2, moderate: Disperse Red 1 and Disperse Blue 1 (3%); group 3, weak: Disperse Orange 37 and Disperse Blue 35 (10%); and group 4, very weak: Disperse yellow 3 and Disperse Orange 3 (increase at 30% or no increase at 30%). In conclusion, our study shows that the biphasic LLNA protocol was proficient enough to study the sensitisation potential of tested textile dyes and provides data allowing to discriminate them according to their potency.

Repeated topical application of glucocorticoids augments irritant chemical-triggered scratching in mice

Topical glucocorticoids, widely used for the treatment of a variety of dermatitises, are known to exacerbate atopic dermatitis after long-term or inappropriate use. In some animal models, topical glucocorticoids augment the allergic cutaneous inflammation after repeated application, suggesting a relationship between these and clinical observations. We investigated whether topical glucocorticoids augment itching, rather than inflammation, resulting in the exacerbation of atopic dermatitis. Mice receiving repeated topical application of glucocorticoids, betamethasone valerate or dexamethasone, to the ear for 1 week showed significantly higher scratching frequency after application of an irritant chemical, 2,4-dinitrofluorobenzene (DNFB) or 12-O-tetradecanoilphorbol 13-acetate (TPA) than those receiving either a glucocorticoid or irritant chemical alone. In contrast, the increase in ear thickness induced by application of TPA was significantly suppressed by dexamethasone. Substance P (SP) and nerve growth factor (NGF) levels were higher in the ear receiving betamethasone valerate followed by DNFB application than in that receiving DNFB alone. In addition, histopathological studies revealed an increased density of nerve fibers in the ear receiving betamethasone valerate or dexamethasone followed by DNFB application. Oral administration of betamethasone valerate was not associated with an increase in either scratching frequency or SP or NGF level in the ear. These results suggest that repeated topical application of glucocorticoids may augment irritant chemical-triggered scratching through an increase in SP and NGF levels and nerve fiber density at the application site. These findings might explain the etiology of the exacerbation of atopic dermatitis and other dermatitises, occurring after long-term or inappropriate use of topical glucocorticoids.

Potential use of iontophoresis for transdermal delivery of NF-κB decoy oligonucleotides

Topical application of nuclear factor-κB (NF-κB) decoy appears to provide a novel therapeutic potency in the treatment of inflammation and atopic dermatitis. However, it is difficult to deliver NF-κB decoy oligonucleotides (ODN) into the skin by conventional methods based on passive diffusion because of its hydrophilicity and high molecular weight. In this study, we evaluated the in vitro transdermal delivery of fluorescein isothiocyanate (FITC)-NF-κB decoy ODN using a pulse depolarization (PDP) iontophoresis. In vitro iontophoretic experiments were performed on isolated C57BL/6 mice skin using a horizontal diffusion cell. The apparent flux values of FITC-NF-κB decoy ODN were enhanced with increasing the current density and NF-κB decoy ODN concentration by iontophoresis. Accumulation of FITC-NF-κB decoy ODN was observed at the epidermis and upper dermis by iontophoresis. In mouse model of skin inflammation, iontophoretic delivery of NF-κB decoy ODN significantly reduced the increase in ear thickness caused by phorbol ester as well as the protein and mRNA expression levels of tumor necrosis factor-α (TNF-α) in the mice ears. These results suggest that iontophoresis is a useful and promising enhancement technique for transdermal delivery of NF-κB decoy ODN.

Suppression of Experimental Inflammation by Anti-fungal Agent Liranaftate in Mice

To evaluate the anti-inflammatory activity of the thiocarbamate antifungal agent liranaftate, the edema and the neutrophil accumulation detected by the activity of neutrophil marker enzyme, myeloperoxidase (MPO), were examined following application of liranaftate to mouse ears with inflammation induced by phorbol 12-myristate 13-acetate (PMA). Topical 20 microl administration of liranaftate in a dose-range between 1-4% suppressed the increase in ear thickness 6 hr after PMA application dose-dependently. Similarly, it decreased the weight increase of an ear section after 24 hr dose-dependently. More than 1% of liranaftate also suppressed augmentation of MPO activity of the ear section. This and histological observation indicate that liranaftate treatment suppressed neutrophil accumulation in PMA-applied ear lesion. From these results, we discussed that liranaftate might suppress inflammatory symptoms caused by trychophytosis in a clinical condition.

Effects and mechanisms of aloperine on 2, 4-dinitrofluorobenzene-induced allergic contact dermatitis in BALB/c mice

Allergic contact dermatitis is a prototypic T-cell-mediated cutaneous inflammatory response. Multiple cell types, inflammatory mediators and cytokines are involved in the regulation of immunologic and inflammatory processes in allergic contact dermatitis. Aloperine is an isolated alkaloid found in the plant of Sophora alopecuroides L. It has been clinically proved effective in China for a long time for skin inflammatory diseases such as allergic contact dermatitis. However, the mechanism of aloperine on allergic contact dermatitis is largely unknown. Therefore, the aim of this study was to investigate the effect of aloperine on 2, 4-dinitrofluorobenzene (DNFB)-induced allergic contact dermatitis in BALB/c mice and the possible underlying mechanisms. The results showed that topical application of DNFB on the ear provoked typical allergic contact dermatitis with ear swelling and ear erythema in BALB/c mice. Treatments with 1% aloperine suppressed DNFB-induced increase in ear thickness and ear erythema. Moreover, 1% aloperine treatment significantly decreased the up-regulated mRNA and protein levels of tumor necrosis factor-alpha (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6) induced by DNFB in ear biopsy homogenates. Our findings suggest that aloperine greatly improves the DNFB-induced allergic contact dermatitis in mice. The therapeutic mechanism might be related to the reduction of TNF-α, IL-1β and IL-6 production induced by DNFB.

Melatonin inhibits the development of 2,4‐dinitrofluorobenzene‐induced atopic dermatitis‐like skin lesions in NC/Nga mice

Atopic dermatitis (AD) is a common disease in children, and epicutaneous treatment with a chemical hapten such as 2,4-dinitrofluorobenzene (DNFB) evokes an AD-like reaction in NC/Nga mice under specific pathogen-free conditions. Melatonin (N-acetyl-5-methoxytryptamine) is synthesized by the pineal gland, has several different physiologic functions, which include seasonal reproduction control, immune system modulation, free radical scavenging, and inflammatory suppression. In the present study, we investigated whether melatonin suppresses DNFB-induced AD-like skin lesions in NC/Nga mice. The topical administration of melatonin to DNFB-treated NC/Nga mice was found to inhibit ear thickness increases and the skin lesions induced by DNFB. Furthermore, interleukin (IL)-4 and interferon (IFN)-gamma secretion by activated CD4(+) T cells from the draining lymph nodes of DNFB-treated NC/Nga mice were significantly inhibited by melatonin, and total IgE levels in serum were reduced. Our findings suggest that melatonin suppresses the development of AD-like dermatitis in DNFB-treated NC/Nga mice by reducing total IgE in serum, and IL-4 and IFN-gamma production by activated CD4(+) T cells.

Administration of Melatonin Inhibits the development of DNFB-induced Dermatitis in NC/Nga Mice (36.9)

Abstract Epicutaneously administered chemical haptens like 2, 4-dinitrofluorobenzene (DNFB) evoke an Atopic dermatitis (AD)-like dermatitis reaction in NC/Nga mice under Specific Pathogen Free (SPF) conditions. Melatonin (N-Acetye-5-methoxytryptamine, MA), synthesized by pineal gland, has different physiological functions, including control of seasonal reproduction, immnune system modulation, anti-aging effect, and function as a free radical scavenger. In the present study, we examined whether treatment with MA suppress AD-like skin lesions in NC/Nga mice treated with DNFB under SPF conditions. Intraperitonealy (i.p.) administration of MA to DNFB-treated NC/Nga mice was found to inhibit ear thickness increases and the skin lesions induced by DNFB. IL-4 and IFN-γ production by activated CD4+T cells from the lymph nodes of DNFB-treated NC/Nga mice was significantly inhibited by MA treatment. Moreover, total IgE level in serum was decreased by MA treatment. Our findings suggest that MA may suppress the development of AD-like dermatitis in DNFB-treated NC/Nga mice by reducing total IgE in serum, IL-4 and IFN-γ production of activated CD4+T cells.

Oral administration of Uncariae rhynchophylla inhibits the development of DNFB-induced atopic dermatitis-like skin lesions via IFN-γ down-regulation in NC/Nga mice

Ethnopharmacological relevance Uncariae rhynchophylla (UR) is an herb which has blood pressure lowering and anti-inflammatory effects and has been prescribed traditionally to treat stroke and vascular dementia. Aim of study In the present study, we examined whether UR suppress Atopic dermatitis (AD)-like skin lesions in NC/Nga mice treated with 2, 4-dinitrofluorobenzene (DNFB) under SPF conditions. Material and methods The effect of UR in DNFB- treated NC/Nga mice was determined by measuring the skin symptom severity, levels of serum IgE, and of the amounts of IL-4 and IFN-γ secreted by activated T cells in draining lymph nodes. Results Oral administration of UR to DNFB-treated NC/Nga mice was found to inhibit ear thickness increases and the skin lesions induced by DNFB. IFN-γ production by CD4+ T cells from the lymph nodes of DNFB-treated NC/Nga mice was significantly inhibited by UR treatment, although levels of IL-4 and total IgE in serum were not. Conclusion UR may suppress the development of AD-like dermatitis in DNFB-treated NC/Nga mice by reducing IFN-γ production.

Effect of orally administered KF66490, a phosphodiesterase 4 inhibitor, on dermatitis in mouse models

Due to the broad anti-inflammatory and immunomodulatory actions of phosphodiesterase (PDE) 4 inhibitors, it has been proposed that PDE4 inhibitors might be efficacious for skin disorders such as atopic dermatitis. KF66490 is a newly developed PDE4 inhibitor that inhibits PDE4B (IC 50 = 220 nM) and the production of tumor necrosis factor (TNF)-α by mouse peritoneal exudated cells stimulated with lipopolysaccharide (IC 50 = 855 nM). To evaluate efficacy of KF66490 in atopic dermatitis (AD) models, on skin inflammation induced by repeated application of 2,4,6-trinitro-1-chlorobenzene (TNCB) on ear in BALB/c mice and on spontaneously AD-like skin diseases in NC/Nga mice. BALB/c mice were sensitized with 0.3% w/v TNCB applied to the ear on day-7, followed by application three times a week from days 0 to 21. NC/Nga mice spontaneously developed dermatitis symptoms under conventional conditions. Test compounds were administered orally once daily during experiments. In the TNCB-induced dermatitis model, KF66490 significantly inhibited the increase in ear thickness and interleukin (IL)-4 and IL-1β levels in the ear. Histopathological and immunohistochemical analysis revealed that KF66490 significantly inhibited the proliferation of fibroblasts and CD3-positive T cells infiltration into the ear. In addition, KF66490 significantly suppressed the development of dermatitis in NC/Nga mice on all observation days, except for 5 and 6 weeks after the first dose. Furthermore, KF66490 produced less potent emetic effects than the first generation PDE4 inhibitor, rolipram. The present results suggest that KF66490 has excellent potential as an oral medicine for the treatment of atopic dermatitis.