A Novel Model for Human Atopic Dermatitis: Application of Repeated DNCB Patch in BALB/c Mice, in Comparison with NC/Nga Mice

Phyllostachys nigra Munro var alleviates inflammatory chemokine expression and DNCB-induced atopic-like dermatitis in BALB/c mice

ETHNOPHARMACOLOGICAL RELEVANCE

Phyllostachys nigra (PN) is an herbal medicine that originates from the inner bark of Phyllostachys nigra Munro var. henosis Stapf or Phyllostachys bambusoides Siebold et Zuccarini. It has long been used to relieve fever and to treat diarrhea and inflammation. PN has been shown to possess inhibitory effects on pneumonia, intestinal inflammation, tumors, and fatigue. However, its potential efficacy in the treatment of atopic dermatitis (AD) has not been extensively studied or reported.

AIM OF THE STUDY

The objective of this research was to investigate the impact of PN on HaCaT and HMC-1 cells, as well as its potential in an experimental model of AD induced by 1-chloro-2,4-dinitrobenzene (DNCB).

METHODS

We analyzed the anti-inflammatory efficacy of PN in HaCaT cells and HMC-1 cells using ELISA and PCR, and investigated invasion of inflammatory cell, change of dermis and epidermis, and the SCORAD index in AD-like mice model. We also measured the MAPK signaling pathway using the dorsal tissue of mice.

RESULTS

Our results show that PN reduced the expressions of TARC, GM-CSF, TNF-α, MCP-1, and IL-6 in vitro. PN also decreased the SCORAD index, thickening of epidermis and dermis, and inhibited the invasions of mast cells and eosinophils as well as CD4+ T and CD8+ T cells. Furthermore, PN suppressed the level of IgE and IL-6, and also inhibited the MAPK phosphorylation in the dorsal skin.

CONCLUSION

These results demonstrate that PN could be an effective alternative medicine for allergic inflammatory disease.

Canine amniotic membrane-derived mesenchymal stem cells ameliorate atopic dermatitis through regeneration and immunomodulation

Mesenchymal stem cells (MSCs) are a promising tool for treating immune disorders. However, the immunomodulatory effects of canine MSCs compared with other commercialized biologics for treating immune disorders have not been well studied. In this study we investigated the characteristics and immunomodulatory effects of canine amnion membrane (cAM)-MSCs. We examined gene expression of immune modulation and T lymphocytes from activated canine peripheral blood mononuclear cell (PBMC) proliferation. As a result, we confirmed that cAM-MSCs upregulated immune modulation genes (TGF-β1, IDO1 and PTGES2) and suppressed the proliferation capacity of T cells. Moreover, we confirmed the therapeutic effect of cAM-MSCs compared with oclacitinib (OCL), the most commonly used Janus kinase (JAK) inhibitor, as a treatment for canine atopic dermatitis (AD) using a mouse AD model. As a result, we confirmed that cAM-MSCs with PBS treatment groups (passage 4, 6 and 8) compared with PBS only (PBS) though scores of dermatologic signs, tissue pathologic changes and inflammatory cytokines were significantly reduced. In particular, cAM-MSCs were more effective than OCL in the recovery of wound dysfunction, regulation of mast cell activity and expression level of immune modulation protein. Interestingly, subcutaneous injection of cAM-MSCs induced weight recovery, but oral administration of oclacitinib induced weight loss as a side effect. In conclusion, this study suggests that cAM-MSCs can be developed as a safe canine treatment for atopic dermatitis without side effects through effective regeneration and immunomodulation.

Effects of Magnoliae Flos on Atopic Dermatitis-Like Inflammation Evaluated via Extracellular Signal-regulated Kinase or Signal Transducers and Activators of Transcription 1/3 Signalling Pathways

Atopic dermatitis is a chronic inflammatory skin  disease. Skin is the largest organ and plays a pivotal role in protecting the body. Not only does the skin act as a physical barrier against the external environment, but it also has its own immune system. Atopic dermatitis is caused by prolonged excessive inflammatory responses that worsen under imbalanced cutaneous immune system skin conditions. Although the prevalence and burden of atopic dermatitis is increasing, the standard therapeutic agents remain unclear due to  the complicated pathophysiology of the condition. The objective of this study is to examine the use of Magnoliae flos, the dried flower bud of Magnolia biondii or  related plants. The effects and underlying mechanism of  action of aqueous extract of the buds of Magnoliae flos (MF) were evaluated. Immortalized human keratinocytes (HaCaT) stimulated with tumour necrosis factor-α and interferon-γ mixture and NC/Nga mice stimulated with 2,4-dinitrochlorobenzene were used as atopic dermatitis models, in vitro and in vivo, respectively. The effects of MF were determined by measuring the suppression of pro-inflammatory signalling pathways, such as extracellular signal-regulated kinase or signal transducers and activators of transcription 1/3 and restoring skin barrier molecules. In conclusion, MF is a potential therapeutic alternative for the treatment of atopic dermatitis through repressing inflammatory pathways.

The Anti-Atopic Dermatitis Effects of Mentha arvensis Essential Oil Are Involved in the Inhibition of the NLRP3 Inflammasome in DNCB-Challenged Atopic Dermatitis BALB/c Mice

The NLRP3 inflammasome is upregulated by various agents, such as nuclear factor-kappa B (NF-κB), lipopolysaccharide (LPS), and adenosine triphosphate (ATP). The NLRP3 inflammasome facilitations the maturation of interleukin (IL)-1β, a proinflammatory cytokine that is critically involved in the pathogenesis of atopic dermatitis (AD). Although the NLRP3 inflammasome clearly exacerbates AD symptoms such as erythema and pruritus, drugs for AD patients targeting the NLRP3 inflammasome are still lacking. Based on the previous findings that Mentha arvensis essential oil (MAEO) possesses strong anti-inflammatory and anti-AD properties through its inhibition of the ERK/NF-κB signaling pathway, we postulated that MAEO might be capable of modulating the NLRP3 inflammasome in AD. The aim of this research was to investigate whether MAEO affects the inhibition of NLRP3 inflammasome activation in murine bone marrow-derived macrophages (BMDMs) stimulated with LPS + ATP in vitro and in a murine model displaying AD-like symptoms induced by 2,4-dinitrochlorobenzene (DNCB) in vivo. We found that MAEO inhibited the expression of NLRP3 and caspase-1, leading to the suppression of NLRP3 inflammasome activation and IL-1β production in BMDMs stimulated with LPS + ATP. In addition, MAEO exhibited efficacy in ameliorating AD symptoms in a murine model induced by DNCB, as indicated by the reduction in dermatitis score, ear thickness, transepidermal water loss (TEWL), epidermal thickness, and immunoglobulin E (IgE) levels. Furthermore, MAEO attenuated the recruitment of NLRP3-expressing macrophages and NLRP3 inflammasome activation in murine dorsal skin lesions induced by DNCB. Overall, we provide evidence for the anti-AD effects of MAEO via inhibition of NLRP3 inflammasome activation.

Anti-inflammatory and immunomodulatory effects of polysaccharide extracted from Wuguchong (maggot) on 2,4-dinitrochlorobenzene-induced atopic dermatitis in mice

Atopic dermatitis (AD) is an inflammatory, heterogeneous, chronic skin disorder characterized by recurrent eczematous lesions and intense pruritus, and the pathophysiology mechanism of AD is known for immune dysregulation and inflammatory responses. Wuguchong (maggot) has been widely used in the wound field and found with pharmacological properties of the anti-inflammatory and immunomodulatory function. Recently, some polysaccharides were proven to have beneficial effects on AD skin lesions in mice and humans. However, the effect of the polysaccharide extracted from Wuguchong (PEW) on AD remains to be investigated. In the present study, we examined the anti-inflammatory and immunomodulatory effects of PEW on AD and explored the potential mechanisms. Balb/c mice were orally administrated with PEW to evaluate the therapeutic effect of PEW on 2,4-dinitrochlorobenzene (DNCB)-induced AD. Oral PEW administration significantly ameliorated the lesions and symptoms in AD mice, such as the ear thickness and ear swelling degree, epidermal and dermal thickness, and the infiltration of mast cells. In addition, PEW treatment decreased the levels of serum IgE and histamine, the frequencies of Th1 and Th17 cells, as well as the mRNA expression levels of Th1 and Th17 cytokines and nuclear transcript factors (IFN-γ, T-bet, IL-17A, and ROR-rt). Furthermore, the activation of the NF-κB pathway and the phosphorylation of MAPKs (p38, ERK, and JNK) were significantly suppressed by PEW treatment. Taken together, our study suggests that PEW exerts anti-inflammatory and immunomodulatory effects through inhibition of Th1 and Th17 responses and downregulation of NF-κB and MAPK pathways, PEW would be developed as a promising immune therapy for AD.

Management of Atopic Dermatitis Via Oral and Topical Administration of Herbs in Murine Model: A Systematic Review

Over the past few decades, complementary and alternative medicine (CAM) using herbs, or their active constituents have garnered substantial attention in the management of a chronic and relapsing inflammatory skin disorder called atopic dermatitis (AD), particularly in attenuating disease recurrence and maintaining long-term remission. In Eastern Asian countries including China, Korea and Taiwan, herbal medicine available in both topical and oral preparation plays a significant role in treating skin diseases like AD as they possibly confer high anti-inflammatory properties and immunomodulatory functions. Conventional murine models of AD have been employed in drug discovery to provide scientific evidence for conclusive and specific pharmacological effects elicited by the use of traditional herbs and their active constituents. Coupled with the goal to develop safe and effective novel therapeutic agents for AD, this systematic review consists of a summary of 103 articles on both orally and topically administered herbs and their active constituents in the murine model, whereby articles were screened and selected via a specialized framework known as PICO (Population, Intervention, Comparator and Outcome). The objectives of this review paper were to identify the efficacy of oral and topical administered herbs along with their active constituents in alleviating AD and the underlying mechanism of actions, as well as the animal models and choice of inducer agents used in these studies. The main outcome on the efficacy of the majority of the herbs and their active constituents illustrated suppression of Th2 response as well as improvements in the severity of AD lesions, suppression of Immunoglobulin E (IgE) concentration and mast cell infiltration. The majority of these studies used BALB/c mice followed by NC/Nga mice (commonly used gender-male; commonly used age group - 6-8 weeks). The most used agent in inducing AD was 2, 4-Dinitrochlorobenzene (DNCB), and the average induction period for both oral and topical administered herbs and their active constituents in AD experiments lasted between 3 and 4 weeks. In light of these findings, this review paper could potentially assist researchers in exploring the potential candidate herbs and their active constituents using murine model for the amelioration of AD.

Dendrobium nobile Lindley Administration Attenuates Atopic Dermatitis-like Lesions by Modulating Immune Cells

Atopic dermatitis (AD) is a chronic inflammatory skin disease that can significantly affect daily life by causing sleep disturbance due to extreme itching. In addition, if the symptoms of AD are severe, it can cause mental disorders such as ADHD and suicidal ideation. Corticosteroid preparations used for general treatment have good effects, but their use is limited due to side effects. Therefore, it is essential to minimize the side effects and study effective treatment methods. Dendrobium nobile Lindley (DNL) has been widely used for various diseases, but to the best of our knowledge, its effect on AD has not yet been proven. In this study, the inhibitory effect of DNL on AD was confirmed in a DNCB-induced Balb/c mouse. In addition, the inhibitory efficacy of inflammatory cytokines in TNF-α/IFN-γ-induced HaCaT cells and PMACI-induced HMC-1 cells was confirmed. The results demonstrated that DNL decreased IgE, IL-6, IL-4, scratching behavior, SCORAD index, infiltration of mast cells and eosinophils and decreased the thickness of the skin. Additionally, DNL inhibited the expression of cytokines and inhibited the MAPK and NF-κB signaling pathways. This suggests that DNL inhibits cytokine expression, protein signaling pathway, and immune cells, thereby improving AD symptoms in mice.

Indigo Pulverata Levis (Chung-Dae, Persicaria tinctoria) Alleviates Atopic Dermatitis-like Inflammatory Responses In Vivo and In Vitro

Atopic dermatitis (AD) is a chronic inflammatory skin disease associated with a type 2 T helper cell (Th2) immune response. The IndigoPulverata Levis extract (CHD) is used in traditional Southeast Asian medicine; however, its beneficial effects on AD remain uninvestigated. Therefore, we investigated the therapeutic effects of CHD in 2,4-dinitrochlorobenzene (DNCB)-induced BALB/c mice and tumor necrosis factor (TNF)-α- and interferon gamma (IFN)-γ-stimulated HaCaT cells. We evaluated immune cell infiltration, skin thickness, and the serum IgE and TNF-α levels in DNCB-induced AD mice. Moreover, we measured the expression levels of pro-inflammatory cytokines, mitogen-activated protein kinase (MAPK), and the nuclear factor-kappa B (NF-κB) in the mice dorsal skin. We also studied the effect of CHD on the translocation of NF-κB p65 and inflammatory chemokines in HaCaT cells. Our in vivo results revealed that CHD reduced the dermis and epidermis thicknesses and inhibited immune cell infiltration. Furthermore, it suppressed the proinflammatory cytokine expression and MAPK and NF-κB phosphorylations in the skin tissue and decreased serum IgE and TNF-α levels. In vitro results indicated that CHD downregulated inflammatory chemokines and blocked NF-κB p65 translocation. Thus, we deduced that CHD is a potential drug candidate for AD treatment.

Mentha arvensis Essential Oil Exerts Anti-Inflammatory in LPS-Stimulated Inflammatory Responses via Inhibition of ERK/NF-κB Signaling Pathway and Anti-Atopic Dermatitis-like Effects in 2,4-Dinitrochlorobezene-Induced BALB/c Mice

The mechanism of atopic dermatitis (AD) is modulated by the release of cytokines and chemokines through the mitogen-activated protein kinase (MAPK)/nuclear factor-kappa B (NF-κB) signaling pathway. Topical steroids are used to treat AD, but some people need safer anti-inflammatory drugs to avoid side effects. Mentha arvensis has been used as a herbal plant with medicinal properties, but its anti-inflammatory effects have not been elucidated in an AD model. In this study, we investigated the anti-inflammatory effects of M. arvensis essential oil (MAEO) and its underlying molecular mechanism in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages and HaCaT cells (human epidermal keratinocyte). Additionally, we examined the ameliorating effects of the MAEO in a dinitrochlorobenzene (DNCB)-induced murine model of AD. We found, in both RAW 264.7 cells and HaCaT cells, MAEO inhibited LPS-stimulated inflammatory mediators such as nitric oxide (NO) and prostaglandin E₂ and proinflammatory cytokines, including IL-1β and IL-6, due to the suppression of COX-2 and iNOS expression. In LPS-stimulated macrophages, we also observed that MAEO inhibited the phosphorylation of ERK and P65. Furthermore, MAEO treatment attenuated AD symptoms, including the dermatitis score, ear thickness, epidermal thickness and infiltration of mast cells, in a DNCB-induced animal model of AD. Overall, our findings suggest that MAEO exerts anti-inflammatory and anti-atopic dermatitis effects via inhibition of the ERK/NF-κB signaling pathway.

Immunomodulation and mechanisms of fucoidan from Cladosiphon okamuranus ameliorates atopic dermatitis symptoms

Atopic dermatitis (AD) is a long-term allergic skin disorder that occurs most frequently in children. Currently, the common treatment of AD is corticosteroids; however, the drugs cause serious side effects. Therefore, there are many patients who seek complementary and alternative treatments such as healthy food. We report that fucoidan from Cladosiphon okamuranus (COP) exhibit exceptional immuno-modulatory effects significantly improving atopic dermatitis (AD) at both in vitro and in vivo levels: First, we performed the P815 cell degranulation assay, of which the results revealed that COP possesses anti-degranulation activity suggesting COP is very conducive to relieving allergic reactions of AD. Next, we performed the animal model examination, of which AD was significantly improved, suggesting COP can focally and globally modulate the immune systems of animals. The systemic improvements were manifested clearly by decreased epidermal hyperplasia, reduced infiltration of eosinophils, and decreased expression of AD-associated cytokines. Notably, COP reduced epidermal hyperplasia by downregulating the expression of IL-22. COP displayed therapeutic effects, which is comparable to corticosteroids but lack corticosteroid side effects, such as weight loss in our animal study. COP is multitudinous immunomodulatory abilities to serve as a healthy food supplement at the current stage, not least beneficial to atopic dermatitis.

Effect of low-level laser intervention on dermatitis symptoms and cytokine changes in DNCB-induced atopy mouse model: A randomized controlled trial

The incidence of atopic dermatitis (AD) has recently increased due to various factors. Its prevalence is higher among children and teenagers than in other age groups. Numerous methods to treat AD are available, including light ray therapy, which has been proposed as an alternative therapy for the treatment of AD. The present study aimed to evaluate the curative mechanism and optimal energy level of energy irradiation from a low-level laser (LLL) toward AD. AD was induced in BALB/c mice with dinitrochlorobenzene (DNCB) solution. The mice were divided into six groups, including one normal control (n=8), one AD control (n=10) and four AD experimental groups with LLL irradiation at 2 J/cm² (n=10), 4 J/cm² (n=10), 6 J/cm² (n=9) and 8 J/cm² (n=10). Following AD induction, an LLL was applied to the four AD experimental groups for 2, 4, 6, and 8 min, for two weeks (14 times in total) at a wavelength of 650 nm and an output of 50 mW. The effects of irradiation on AD were evaluated using a scratch test, a clinical skin severity test, immunoglobulin-E (IgE) analysis and measurements of numerous cytokine levels, including interleukin (IL)-4, IL-6, tumor necrosis factor (TNF)-α, and interferon-γ (IFN-γ), tissue thickness and mast cell count. The results demonstrated that serum IgE level in all irradiated groups was significantly decreased compared with that of the AD control group, and IL-4 level was significantly decreased in all irradiated groups apart from the 8 J/cm² LLL irradiated group. IL-6 and TNF-α levels were also significantly decreased in all irradiated groups. The results from histological analysis revealed diminished epidermal thickness and mast cell counts in irradiated mice compared with those mice in the AD control group. In summary, these findings suggested that LLL irradiation may alleviate symptoms of AD and may be useful for restoring cytokines levels and tissues features to normal levels.

Suppression of DNCB-Induced Atopic Skin Lesions in Mice by Wikstroemia indica Extract

Wikstroemia indica (L.) C.A. Mey. is used in traditional Chinese medicine to treat inflammatory diseases such as arthritis and bronchitis. In this study, we aimed to investigate the effects of an ethanolic extract of W. indica on cutaneous inflammation in mice with 2,4-dinitrochlorobenzene (DNCB)-induced atopic dermatitis (AD). Dermal administration of W. indica ethanolic extract to DNCB-sensitized hairless mice with dermatitis, for two weeks, reduced erythema, scaling, and edema. Skin hydration was improved and transepidermal water loss was reduced at a W. indica concentration of 1%. Furthermore, W. indica also significantly reduced serum IgE and IL-4 concentrations in our mouse model. These results suggest that W. indica has potential as a topical treatment for AD and as an adjunctive agent to control AD.

Topical Spilanthol Inhibits MAPK Signaling and Ameliorates Allergic Inflammation in DNCB-Induced Atopic Dermatitis in Mice

Atopic dermatitis (AD) is a recurrent allergic skin disease caused by genetic and environmental factors. Patients with AD may experience immune imbalance, increased levels of mast cells, immunoglobulin (Ig) E and pro-inflammatory factors (Cyclooxygenase, COX-2 and inducible NO synthase, iNOS). While spilanthol (SP) has anti-inflammatory and analgesic activities, its effect on AD remains to be explored. To develop a new means of SP, inflammation-related symptoms of AD were alleviated, and 2,4-dinitrochlorobenzene (DNCB) was used to induce AD-like skin lesions in BALB/c mice. Histopathological analysis was used to examine mast cells and eosinophils infiltration in AD-like skin lesions. The levels of IgE, IgG1 and IgG2a were measured by enzyme-linked immunosorbent assay (ELISA) kits. Western blot was used for analysis of the mitogen-activated protein kinase (MAPK) pathways and COX-2 and iNOS protein expression. Topical SP treatment reduced serum IgE and IgG2a levels and suppressed COX-2 and iNOS expression via blocked mitogen-activated protein kinase (MAPK) pathways in DNCB-induced AD-like lesions. Histopathological examination revealed that SP reduced epidermal thickness and collagen accumulation and inhibited mast cells and eosinophils infiltration into the AD-like lesions skin. These results indicate that SP may protect against AD skin lesions through inhibited MAPK signaling pathways and may diminish the infiltration of inflammatory cells to block allergic inflammation.

Topical Application of JAK1/JAK2 Inhibitor Momelotinib Exhibits Significant Anti-Inflammatory Responses in DNCB-Induced Atopic Dermatitis Model Mice

Atopic dermatitis (AD) is a chronic recurrent skin disease dominated by T-helper 2 inflammation. Momelotinib (MMB) is a novel JAK1/JAK2 inhibitor suppressing the signal transduction of multiple pro-inflammatory cytokines. Recent studies indicated that JAK inhibitor could play a therapeutic role in AD disease. In this study, we evaluated the efficacy of MMB as a novel JAK1/JAK2 inhibitor in DNCB-induced AD mice and TSLP-activated dendritic cells. Our data showed that topical application of MMB reduced the skin severity scores and total serum IgE levels, and alleviated the histological indexes including epidermal thickness measurement and mast cell number. Also, it was demonstrated that MMB down-regulated the mRNA expression of IL-4, IL-5, IFN-γ and TSLP, and inhibited the phosphorylation of STAT1, STAT3 and STAT5 in skin lesions. Moreover, MMB reduced the expression of CD80, CD86, MHCII and mRNA of OX40L in TSLP-activated dendritic cells. In general, our study suggests that MMB can improve the symptoms of AD and topical application of MMB can become a promising new therapy strategy for AD.

Therapeutic effects of bee venom and its major component, melittin, on atopic dermatitis in vivo and in vitro

BACKGROUND AND PURPOSE

Atopic dermatitis (AD) is a multifactorial skin condition with complex interactions of innate and adaptive immune responses. There are several existing therapies for AD, including topical glucocorticosteroids, emollients, phototherapies, calcineurin inhibitors and immunosuppressants, such as cyclosporine A. Although these therapies reduce inflammation, they also cause serious side effects. Therefore, it is necessary to develop new therapeutic approaches for AD treatment without side effects. There are several studies on natural materials or toxins, such as herbs, ginseng extract and snake venom, for AD treatment. However, treatment of AD with bee venom and its major component, melittin has rarely been studied.

EXPERIMENTAL APPROACH

Effects of bee venom and melittin were studied in a model of AD in vivo induced by 1-chloro-2,4-dinitrobenzene (DNCB) in female Balb/c mice and in cultures of human keratinocytes, stimulated by TNF-α/IFN-γ. The potential pharmacological effects of bee venom and melittin on these in vivo and in vitro AD-like skin disease models were studied.

KEY RESULTS

Bee venom and melittin exhibited potent anti-atopic activities, shown by decreased AD-like skin lesions, induced by DNCB in mice. In vitro studies using TNF-α/IFN-γ-stimulated human keratinocytes showed that bee venom and melittin inhibited the increased expression of chemokines, such as CCL17 and CCL22, and pro-inflammatory cytokines, including IL-1β, IL-6 and IFN-γ, through the blockade of the NF-κB and STAT signalling pathways.

CONCLUSIONS AND IMPLICATIONS

Our results suggest that bee venom and melittin would be suitable for epicutaneous application, as topical administration is often appropriate for the treatment of AD.

Topical administration of EGF suppresses immune response and protects skin barrier in DNCB-induced atopic dermatitis in NC/Nga mice

Atopic dermatitis (AD) is a common inflammatory skin disease characterized by a complex, heterogeneous pathogenesis including skin barrier dysfunction, immunology, and pruritus. Although epidermal growth factor (EGF) is essential for epithelial homeostasis and wound healing, the effect of EGF on AD remains to be explored. To develop a new therapy for AD, the anti-AD potential of EGF was investigated by inducing AD-like skin lesions in NC/Nga mice using 2,4-dinitrochlorobenzene (DNCB). EGF was administrated to NC/Nga mice to evaluate its therapeutic effect on DNCB-induced AD. EGF treatment improved dermatitis score, ear thickness, epidermal hyperplasia, serum total immunoglobulin E level, and transepidermal water loss in NC/Nga mice with DNCB-induced AD. In addition, levels of skin barrier-related proteins such as filaggrin, involucrin, loricrin, occludin, and zonula occludens-1 (ZO-1) were increased by EGF treatment. These beneficial effects of EGF on AD may be mediated by EGF regulation of Th1/Th2-mediated cytokines, mast cell hyperplasia, and protease activated receptor-2 (PAR-2) and thymic stromal lymphopoietin (TSLP), which are triggers of AD. Taken together, our findings suggest that EGF may potentially protect against AD lesional skin via regulation of skin barrier function and immune response.

Cryptotanshinone inhibits IgE‑mediated degranulation through inhibition of spleen tyrosine kinase and tyrosine‑protein kinase phosphorylation in mast cells

Atopic dermatitis (AD) is a type of chronic skin inflammation and one of the most common relapsing allergic diseases, which presents with a severe rash and itchy skin lesions. The pathogenesis of AD is primarily associated with hyper‑activated mast cells, which makes them an effective treatment target. After cross‑linking the antigen/immunoglobulin (Ig) E complex binds to its high affinity receptor FcεRl on the surface of mast cells. The cells subsequently secrete excessive pro‑inflammatory mediators, including histamine and cytokines, which lead to pruritus and immune cell infiltration in the skin lesions. The present study screened natural compounds that have an inhibitory effect on IgE/antigen‑mediated secretory activity. It was revealed that cryptotanshinone (CRT), a natural compound extracted from Salvia miltiorrhiza Bunge, had inhibitory effects on the IgE/antigen complex. The underlying mechanism by which CRT exerted an anti‑allergy/inflammatory function was investigated using rat basophilic leukaemia (RBL) cells for degranulation assays and a 1‑chloro‑2,4‑dinitrobenzene (DNCB)‑induced AD Balb/c mouse model for in vivo study. CRT effectively mitigated the secretion of pro‑inflammatory cytokines, including tumor necrosis factor‑α and interleukin 1β, as well as immune cell infiltration into skin lesions in a mouse model of AD‑like skin disease induced by dinitrochlorobenzene. The inhibitory effect of CRT on IgE‑mediated mast cell degranulation was mediated by the inhibition of tyrosine kinase‑dependent degranulation signalling pathways involving spleen tyrosine kinase and Lyn. The present study revealed CRT as an inhibitor of mast cell degranulation. Therefore, CRT may be considered for development as a therapeutic drug to treat IgE‑mediated skin diseases.

Inhibitory Effect of Valencene on the Development of Atopic Dermatitis-Like Skin Lesions in NC/Nga Mice

Valencene (VAL) isolated from Cyperus rotundus possesses various biological effects such as antiallergic and antimelanogenesis activity. We investigated the effect of VAL on atopic dermatitis (AD) skin lesions and their molecular mechanisms. We topically applied VAL to 1-chloro-2,4-dinitrobenzene (DNCB) sensitized NC/Nga mice. Modified scoring atopic dermatitis index, scratching behavior, and histological/immunohistochemical staining were used to monitor disease severity. RT-PCR, western blotting, and enzyme-linked immunosorbent assay were used to determine the level of IgE, proinflammatory cytokines/chemokines production, and skin barrier proteins expression. Topical application of VAL significantly reduced AD-like symptoms and recovered decreased expression of filaggrin in DNCB-sensitized NC/Nga mice. The levels of serum IgE, IL-1β, IL-6, and IL-13 in skin/splenic tissue were reduced. In vitro studies using TNF-α and IFN-γ treated HaCaT cells revealed that VAL inhibited the exaggerated expression of Th2 chemokines including TARC/CCL17, MDC/CCL22, and proinflammatory chemokines such as CXCL8, GM-CSF, and I-CAM through blockade of the NF-κB pathway. In addition, expression of the skin barrier protein, involucrin, was also increased by VAL treatment. VAL inhibited the production and expression of proinflammatory cytokines IL-1β and IL-6 in LPS-stimulated RAW 264.7 cells. These results suggest that VAL may serve as a potential therapeutic option for AD.

Bee venom acupuncture alleviates trimellitic anhydride-induced atopic dermatitis-like skin lesions in mice

BACKGROUND

Bee venom acupuncture (BVA), a novel type of acupuncture therapy in which purified bee venom is injected into the specific acupuncture point on the diseased part of the body, is used primarily for relieving pain and other musculoskeletal symptoms. In the present study, therapeutic potential of BVA to improve atopic dermatitis, a representative allergic dysfunction, was evaluated in the mouse model of trimellitic anhydride (TMA)-induced skin impairment.

METHODS

Mice were treated with 5% TMA on the dorsal flank for sensitization and subsequently treated with 2% TMA on the dorsum of both ears for an additional 12 days after a 3-day interval. From the 7(th) day of 2% TMA treatment, bilateral subcutaneous injection of BV (BV, 0.3 mg/kg) was performed daily at BL40 acupuncture points (located behind the knee) 1 h before 2% TMA treatment for 5 days.

RESULTS

BVA treatment markedly inhibited the expression levels of both T helper cell type 1 (Th1) and Th2 cytokines in ear skin and lymph nodes of TMA-treated mice. Clinical features of AD-like symptoms such as ear skin symptom severity and thickness, inflammation, and lymph node weight were significantly alleviated by BV treatment. BV treatment also inhibited the proliferation and infiltration of T cells, the production of Th1 and Th2 cytokines, and the synthesis of interleukin (IL)-4 and immunoglobulin E (IgE)-typical allergic Th2 responses in blood. The inhibitory effect of BVA was more pronounced at BL40 acupoint than non-acupuncture point located at the base of the tail.

CONCLUSIONS

These results indicate that BV injection at specific acupuncture points effectively alleviates AD-like skin lesions by inhibiting inflammatory and allergic responses in a TMA-induced contact hypersensitivity mouse model.

Protective effect of diet supplemented with rice prolamin extract against DNCB-induced atopic dermatitis in BALB/c mice

Background

Rice prolamin has been reported to possess antioxidative, anti-inflammatory and immune-promoting properties. This study is aimed to examine the protective effects of dietary rice prolamin extract (RPE) against dinitrochlorobenzene (DNCB)-induced atopic dermatitis (AD)-like skin lesions in mice.

Methods

BALB/c mice were fed diet supplemented with 0–0.1 % RPE for 6 weeks. For the last 2 weeks, 1 % or 0.2 % DNCB was applied repeatedly to the back skin of mice to induce AD-like lesions. Following AD induction, the severity of skin lesions was examined macroscopically and histologically. In addition, the serum levels of IgE, IgG1 and IgG2a were determined by ELISA, and the mRNA expression of IL-4 and IFN-γ in the skin was determined by real-time PCR.

Results

Dietary RPE suppressed the clinical symptoms of DNCB-induced dermatitis as well as its associated histopathological changes such as epidermal hyperplasia and infiltration of mast cells and eosinophils in the dermis. RPE treatment also suppressed the DNCB-induced increase in transepidermal water loss. Dietary RPE inhibited the DNCB-induced enhancement of serum IgE and IgG1 levels, whereas it increased the serum IgG2a level in DNCB-treated mice. In addition, dietary RPE upregulated the IFN-γ mRNA expression and downregulated the IL-4 mRNA expression in the skin of DNCB-treated mice.

Conclusions

The above results suggest that dietary RPE exerts a protective effect against DNCB-induced AD in mice via upregulation of Th1 immunity and that RPE may be useful for the treatment of AD.

Hizikia fusiformis fractions successfully improve atopic dermatitis indices in anti-CD3-stimulated splenocytes and 2,4-dinitrochlorobenzene-treated BALB/c mice

Objectives

In the present study, we aimed to examine whether fractions from an edible sea weed, Hizikia fusiformis, had immunomodulatory effects, particularly an anti-atopic effect, by attenuating the expression of T cell-dependent cytokines using in-vitro and in-vivo animal atopic dermatitis-like models.

Methods

The anti-atopic activities were examined in in vitro, and a 2,4-dinitrochlorobenzene (DNCB)-induced atopic dermatitis-like mouse model using quantitative real-time polymerase chain reaction, electrophoretic-mobility shift and histophathological analysis.

Key findings

Our results showed that the final fraction (F2′) of H. fusiformis contained a higher amount of butanoic acid which was not found in the other fractions, and effectively inhibited T cell activation by inhibiting dephosphorylation of nuclear factor of activated T cells in electrophoretic-mobility shift assay. As a consequence, helper T cell-dependent cytokines, such as interleukin-2, -4 and interferon-γ, were significantly inhibited while activated with an anti-CD3 antibody. We also showed that skin challenged with DNCB successfully recovered when treated with 2.5 mg/kg, comparable to that by 0.25% prednicarbate. These results indicate that F2′ may contribute to inhibit T cell activation by eliminating Th cell-dependent cytokines.

Conclusions

Taken together, we concluded that F2′ containing butanoic acid may be a new functional anti-atopic candidate, which probably acts through nuclear factor of activated T cell inactivation mechanisms.