Inhibitory effects of Rumex japonicus Houtt. on the development of atopic dermatitis-like skin lesions in NC/Nga mice

BACKGROUND: Rumex japonicus Houtt. (RJH) is one of the herbs used in Eastern countries for the treatment of atopic dermatitis (AD). It has been shown to have an antioxidative effect in human skin disease. OBJECTIVES: To examine whether RJH extract (RJH-E) suppresses the development of AD-like skin lesions in NC/Nga mice, which are induced by the repeated application of picryl chloride (PC). METHODS: The efficacy of RJH-E in NC/Nga mice was assessed by measuring symptom severity, scratching behaviour, Staphylococcus aureus numbers on an ear, and serum levels of IgE, interleukin (IL)-4 and interferon (IFN)-gamma. RESULTS: Oral administration of RJH-E to NC/Nga mice treated with PC inhibited the development of AD-like skin lesions as exemplified by a significant decrease in total skin symptom severity scores, and a decrease in hypertrophy, hyperkeratosis and infiltration of inflammatory cells in the skin. The scratching behaviour and numbers of S. aureus, which are known to be exacerbated in AD, were also significantly reduced by RJH-E. No significant change was observed in the serum levels of IFN-gamma, whereas IgE and IL-4 levels were significantly reduced by RJH-E. CONCLUSIONS: These results suggest that RJH-E inhibits the development of AD-like skin lesions in NC/Nga mice by suppressing the T-helper 2 cell response. Our results indicate that RJH treatment could provide an effective alternative therapy for the management of AD.     

Hyperproduction of IFN-gamma by CpG oligodeoxynucleotide-induced exacerbation of atopic dermatitis-like skin lesion in some NC/Nga mice

Under conventional conditions, NC/Nga mice spontaneously develop an atopic dermatitis (AD)-like skin lesion accompanied by immunoglobulin E (IgE) hyperproduction and the expression of T helper 2 (Th2) cytokines. CpG DNA activates a strong interferon-gamma (IFN-gamma)-dominated T helper 1 (Th1) response, while inhibiting Th2-dependent allergies. In this study, we examined whether CpG oligodeoxynucleotide (ODN) could prevent the development of the skin lesions in NC/Nga mice. Sixteen of 26 NC/Nga mice did not exhibit dermatitis after CpG ODN was administered intraperitoneally every 2 wk for a total of five times. CpG ODN administration induced IFN-gamma production, which inhibited the production of Th2 cytokines (interleukin (IL)-4, IL-5, and IL-13) in both spleen and lymph node cells and culminated in a decrease in the serum IgE level. These data suggest that the CpG ODN has a therapeutic effect against AD; however, some mice (10 of 26) treated with CpG ODN exhibited an exacerbation of dermatitis accompanied by the hyperproduction of IFN-gamma, although Th2 cytokines were suppressed. These results suggest that the suppression of Th2 cytokines may not completely prevent dermatitis and that IFN-gamma may play a role in developing dermatitis in some NC/Nga mice.     

Neuropeptides concentrations in the skin of a murine (NC/Nga mice) model of atopic dermatitis

BACKGROUND: It has been reported that the expression of neuropeptides (NPs), and the density and structure of peripheral nerves in atopic dermatitis (AD) are different from those in normal skin. OBJECTIVE: We investigated the role of NPs, in the development of AD with quantitative study of substance P (SP) and calcitonin gene-related peptide (CGRP) in the skin of AD-model mice. METHODS: We measured the NPs in the skin of mice (NC/Nga as AD-model mice, BALB/c and C57BL/6 as control) by enzyme-linked immunosorbentassay (ELISA). Peripheral nerve fibers and SP in the skin were stained by immunohistochemical staining, using anti-PGP9.5 antibody and anti-SP antibody. RESULTS: Under conventional condition, SP concentration in AD-like skin lesions of NC/Nga mice was higher than that in non-affected skin of the same mice. Under specific pathogen-free condition, SP concentration in the skin of NC/Nga mice was higher than that in the skin of BALB/c and C57BL/6 mice. In contrast, CGRP concentration in the skin lesions was lower than that in non-affected skin of NC/Nga mice. SP was detected not only in the nerve fibers in the dermis but also in mast cells in the inflammatory areas. CONCLUSIONS: The skin of NC/Nga mice contains more SP congenitally, and environmental factors may aggravate this abnormal condition. We hypothesize that increase of SP accompanied with a decrease of CGRP in the skin may play important roles in the pathogenesis and development of AD.     

Repeated topical challenge with chemical antigen elicits sustained dermatitis in NC/Nga mice in specific-pathogen-free condition

NC/Nga mice are known to develop skin lesions resembling to atopic dermatitis (AD) in conventional but not in specific-pathogen-free (SPF) condition. An epicutaneous application of 2,4-dinitrofluorobenzene (DNFB) increased skin thickness in C3H as well as NC/Nga mice in SPF environment, and the response was enlarged by repeating the challenge at weekly intervals. Although the skin reaction in C3H mice was ameliorated when the challenge was discontinued after the fifth application, the reaction in NC/Nga mice was sustained at least for 3 wk. Analyses of cytokine production by CD4+ cells from the draining lymph node proximal to the lesions revealed that, unlike C3H mice, NC/Nga mice fail to induce T helper 2 (Th2) cytokine interleukin-4 (IL-4), whereas the level of Th1 cytokine interferon-gamma in NC/Nga mice is equivalent to that of C3H mice. In addition, NC/Nga mice highly expressed IL-12, a cytokine-preventing formation of Th2 response, whereas C3H mice did not. Administration of anti-IL-12 antibody reduced duration of dermatitis in DNFB-treated NC/Nga mice. Taken together, our data suggest that IL-12 plays a role in the persistent skin reaction in NC/Nga mice. The action of IL-12 might be mediated by the decrease in IL-4 production.     

Itch-associated scratching contributes to the development of dermatitis and hyperimmunoglobulinaemia E in NC/Nga mice

Atopic dermatitis (AD) is related to immunoglobulin E (IgE) production, and a type-1 and type-2 helper T cell (Th1/Th2) imbalance has been hypothesized as the aetiology. While itching and scratching are important factors in the development of dermatitis, the mechanisms underlying these phenomena are poorly understood. We investigated the relationship between scratching, transepidermal water loss (TEWL), signs of dermatitis and serum Ig levels in NC/Nga mice, a model of AD. We also sensitized specific pathogen-free (SPF)-NC/Nga mice and BALB/c mice to mite antigen to determine the effects of IgE overproduction on scratching and investigated the involvement of mast cells and T/B cells in the induction of scratching using WBB6F1-W/W(v) mice and C.B.17/Icr-scid mice. Under conventional conditions, the scratch counts increased, followed by increases in TEWL and the inflammation score in NC/Nga mice that were not kept under SPF conditions. However, no change was observed in scratching, TEWL, or signs of dermatitis in mite antigen-sensitized SPF-NC/Nga and BALB/c mice, although the serum total IgE, IgG(1) and IgG(2a) levels increased. The scratch count increased significantly in both the WBB6F1-W/W(v) mice and C.B.17/Icr-scid mice when they were co-housed with skin-lesioned NC/Nga mice, raised under conventional conditions. These results show that IgE overproduction results from itch-associated scratching-induced dermatitis in NC/Nga mice.     

Inhibition of atopic dermatitis-like skin lesions by topical application of a novel ceramide derivative, K6PC-9p, in NC/Nga mice

Atopic dermatitis (AD) is a chronic inflammatory skin disease that commonly begins in childhood. K6PC-9p (N-(Ethyl dihydrogenphosphate)-2-hexyl-3-oxo-decanamide) is a synthetic ceramide derivative of PC-9S (N-Ethanol-2-mirystyl-3-oxo-staramide), which was known to be effective in atopic patients. In this study, we examined the effect of topical application of K6PC-9p on skin inflammation and AD-like skin lesions in mouse models. K6PC-9p dose-dependently inhibited phorbol ester-induced increase in ear thickness in BALB/c mice. Moreover, topical application of K6PC-9p suppressed dust mite extract-induced AD-like skin lesions in NC/Nga mice. Histopathological analysis revealed that both ear swelling and leucocyte infiltration were suppressed by K6PC-9p treatment. K6PC-9p also suppressed IL-4 and TNF-alpha expression in the ears and mast cell infiltration into the ears in NC/Nga mice. Further study demonstrated that K6PC-9p inhibited ConA-induced IL-4 secretion and LPS-induced macrophage activation. Taken together, our results showed that topical application of K6PC-9p exerts beneficial effects in animal model of skin inflammation and AD, suggesting that K6PC-9p might be a promising topical agent for the treatment of inflammatory skin diseases.     

Involvement of IL-31 on scratching behavior in NC/Nga mice with atopic-like dermatitis

Pruritus is an important symptom in atopic dermatitis (AD), but the major pruritogen has not been identified. NC/Nga mice, spontaneously develop an eczematous AD-like skin lesion when kept under conventional conditions, but not under specific pathogen-free (SPF) conditions, have been thought to be an animal model for AD. In this study, to determine whether newly identified cytokine, IL-31, may be involved in pruritus of AD, we examined the IL-31 expression in spontaneous dermatitis model which showed itch-associated long-lasting (over 1.5 s duration) scratching behavior and compared with that of hapten-induced contact dermatitis model without itch-associated long-lasting scratching behavior, using NC/Nga mice. In NC/Nga mice cohabited with NC/Nga mice which developed severe dermatitis for 2 weeks (conventional NC/Nga mice), the numbers of long-lasting scratching counts were significantly increased. Yet in 2,4,6-trinitrochlorobenzene (TNCB)-sensitized and challenged mice (TNCB-applied NC/Nga mice), no significant increase in long-lasting scratching counts was observed. In conventional NC/Nga mice with long-lasting scratching behavior, expression of IL-31 mRNA was increased, while in TNCB-applied NC/Nga mice without long-lasting scratching behavior, the expression of IL-31 mRNA were unchanged. There was a good correlation between the scratching counts and expression of IL-31 mRNA in conventional NC/Nga mice, but not so in TNCB-applied NC/Nga mice. These results suggest that IL-31 causes the itch-associated scratching behavior in conventional NC/Nga mice, an experimental animal model for AD.     

Induction of scratching behaviour and dermatitis in various strains of mice cohabiting with NC/Nga mice with chronic dermatitis

BACKGROUND: NC/Nga (NC) mice with similar pathological and behavioural features as seen in human atopic dermatitis are used as a model of the disease. Under normal circumstances, spontaneous and persistent scratching occurs in NC mice and this can lead to the onset of skin inflammation. OBJECTIVES: We examined the induction of scratching behaviour in NC, BALB/c, ICR and C3H/HeN mice, and of dermatitis in NC and BALB/c mice, by cohabitation with mice with dermatitis. METHODS: NC, BALB/c, ICR and C3H/HeN mice were kept together with NC mice with chronic dermatitis (CNV-NC) for 2 weeks, and the numbers of scratching episodes were counted. NC and BALB/c mice were also kept together with CNV-NC mice for 24 weeks and the skin severity score was assessed. The score was assessed for a further 8 weeks after separation of these mice. RESULTS: The number of scratching episodes in NC, BALB/c, ICR and C3H/HeN mice was increased by cohabitation with CNV-NC mice. Cohabitation with CNV-NC mice led to dermatitis in both NC and BALB/c mice. The number of scratching episodes and the skin severity score in BALB/c mice were about half of those in NC mice. When cohabitation with CNV-NC mice stopped, the number of scratching episodes and the skin severity score decreased in BALB/c mice, but not in NC mice. Changes in the histopathological data of BALB/c mice supported the severity of skin inflammation. CONCLUSIONS: Our study demonstrates that scratching behaviour and dermatitis can be induced in various strains of mice by cohabitation with CNV-NC mice, and that cessation of cohabitation leads to a recovery in BALB/c mice but not in NC mice.     

Therapeutic effects of streptococcal preparation OK-432 on atopic dermatitis-like lesions in NC/Nga mice: possible shift from a Th2- to Th1-predominance

BACKGROUND: The inducement of Th1 cell-mediated immune response, possibly brought about through bacterial stimulation, may serve to control atopic disorders such as atopic dermatitis (AD). The streptococcal preparation, OK-432, has been shown a potent Th1 inducer through the action of IL-12. NC/Nga mice under ordinary conditions have been found to contract dermatitis similar to human AD. OBJECTIVE: Examination was made of the therapeutic effects of OK-432 local intra- and/or subcutaneous injections on AD-like lesions in NC/Nga mice. METHODS: Immunohistochemical staining with IL-4/IL-12p40 and CD80/86 and phosphorylated STAT4/p-STAT6 and RT-PCR for IL-4/IL-12p40 and STAT6/STAT4 mRNA was conducted for the evaluation of OK-432 treatment of spontaneous AD-like lesions in NC/Nga mice. RESULTS: At 5 weeks following injection of OK-432, for treating head and back lesions in NC/Nga mice, 10 of 12 OK-432 treated NC mice were found to have clinically improved quite considerably. On the head and back skin of OK-432-treated mice, IL-12p40/CD80 positive cellular infiltration was conspicuous, in contrast to non-treated mice. IL-4/CD86 positive cellular infiltrates in OK-432-treated mice had decreased significantly more than in non-treated mice and IL-4 mRNA expression was virtually absent in OK-432-treated mice. P-STAT4 positive cells could be seen abundantly present in OK-432-treated mice, and p-STAT6 positive cells were much fewer than in non-treated mice. CONCLUSIONS: OK-432-treatment appears to induce Th1 cellular response and to down-regulate that of the Th2 pathway in AD-like lesions of NC/Nga mice. The present results demonstrate bacterial components from such Streptococcus to likely constitute an effective new therapeutic approach in the treatment of AD.     

Lipoteichoic acid-related molecule derived from the streptococcal preparation, OK-432, which suppresses atopic dermatitis-like lesions in NC/Nga mice

Bacterial stimulation may serve to control atopic disorders such as atopic dermatitis (AD) through inducement of Th1 cell-mediated immune response. The lipoteichoic acid (LTA)-related molecule (okLTA) from streptococcal preparation, OK-432, has been shown to be a potent Th1 inducer through the action of IL-12. Examination was made of the therapeutic effects of this okLTA injected intra- and/or subcutaneously into AD-like lesions in NC/Nga mice, particularly in the vicinity of the suppressor of cytokine signaling (SOCS) regulatory pathways. Using immunohistochemical staining with IL-4/IL-12p40 and phosphorylated STAT6/p-STAT4 and RT-PCR for IL-4/IL-12p40, STAT6/STAT4 and mRNA expression and in situ hybridization of SOCS3 and 5, evaluation was made of the immunoregulatory effects of this okLTA in the treatment of spontaneous AD-like lesions in NC/Nga mice. Following the injection of okLTA, remarkable improvement in the lesions of NC/Nga mice was noted. In okLTA-treated skin, IL-12p40/p-STAT4 positive cellular infiltration was extensive while IL-4/p-STAT6 positive cell infiltration was seen to diminish considerably, compared to untreated NC mice. SOCS3 in situ expression in okLTA-treated mice was noted to be significantly less compared to untreated NC mice, in which the expression was prominent. SOCS5 in situ expression was rather, though not significantly, strong in okLTA-treated mice. okLTA treatment is clearly shown to induce Th1 cellular response and down-regulate immune response in the Th2 pathway through SOCS3 reduction in AD-like lesions of NC/Nga mice. The present results demonstrate that bacterial wall components such as okLTA should serve as an effective new therapeutic approach for treating AD.     

A single dose of interleukin‐31 (IL‐31) causes continuous itch‐associated scratching behaviour in mice

We investigated the effects of a single dose of mouse interleukin‐31 (IL‐31) on scratching behaviour in comparison with spontaneous skin‐lesion‐ or serotonin (5‐HT)‐ induced scratching behaviour in NC/Nga and BALB/c mice. Intradermal (i.d.) injection of IL‐31 caused a gradual increase in long‐lasting scratching (LLS, over 1.5 s) about 3 h after administration followed by a gradual decrease for over 24 h after administration. I.d. injection of IL‐31 significantly increased the total LLS counts/24 h but not short‐lasting scratching (SLS, 0.3–1.5 s). In skin‐lesioned NC/Nga mice, the LLS but not SLS counts were significantly higher than those in non‐skin‐lesioned NC/Nga mice. We also investigated 5‐HT‐induced scratching in BALB/c mice, SLS but not LLS increased immediately after the injection and then decreased to baseline after at 20 min. These results suggest that IL‐31 may participate in the sensation of itching and promote scratching behaviour in skin‐lesioned NC/Nga mice, an animal model of atopic dermatitis (AD).     

α-Lipoic acid suppresses the development of DNFB-induced atopic dermatitis-like symptoms in NC/Nga mice

Atopic dermatitis (AD) is a common skin disease that has complex pathogenic mechanisms. Under specific pathogen-free conditions, repeated epicutaneous treatment of 2-4-dinitrofluorobenzene (DNFB) evokes AD-like clinical symptoms in NC/Nga mice. α-Lipoic acid (α-LA; 1, 2-dithiolane-3-pentanoic acid) is a dietary component that is synthesized in bacteria, yeast, plants, and mammals. α-LA and its reduced form, dihydrolipoic acid, are powerful antioxidants that have many physiological functions, including free radical scavenging of reactive oxygen species, generation of cellular antioxidants, chelation of metal ions, and inflammatory suppression. In this study, we investigated whether α-LA suppresses AD-like skin lesions induced by repeated DNFB application in NC/Nga mice. α-LA significantly suppressed production of interferon (IFN)-γ and interleukin (IL)-4 by activated CD4(+) T cells. We found that the oral administration of α-LA reduced AD-like clinical symptoms and inhibited increases of epidermal thickness in DNFB-induced AD-like skin lesions of NC/Nga mice. Furthermore, total serum IgE levels were dramatically reduced by topical α-LA treatment. Our findings suggest that oral administration of α-LA suppresses the development of AD in DNFB-treated NC/Nga mice and reduces IFN-γ and IL-4 production from activated CD4(+) T cells as well as total serum IgE levels.     

Tenascin-C is upregulated in the skin lesions of patients with atopic dermatitis

BACKGROUND: Tenascin-C is a large, hexameric extracellular matrix glycoprotein that is expressed during embryogenesis, carcinogenesis and wound healing. In normal adult human skin the expression level of tenascin-C is low, but levels are elevated in skin tumors and rise significantly in the dermal compartment during wound healing. Although the expression of tenascin-C could be upregulated by inflammatory cytokines, the role of tenascin-C in atopic dermatitis (AD) is still unclear. OBJECTIVE: To identify genes that plays a role in AD. METHODS: We screened for differentially expressed genes in lesional and non-lesional skin of AD patients using DNA microarray. Then we monitored with quantitative PCR the expression of the novel disease related genes in human keratinocytes or pinnae from NC/Nga mice. RESULTS: We found that tenascin-C gene expression was expressed at higher levels in lesional skin compared to non-lesional skin of the patients, whereas it was not upregulated in the skin of psoriatic patients or healthy controls. In human cultured keratinocytes, tenascin-C was markedly upregulated by IL-4 and IL-13, and moderately upregulated by IFN-gamma. Tenascin-C expression was also upregulated in the AD-like skin lesions induced in NC/Nga mice ears by intradermal injection of mite antigen, and this upregulation was inhibited by prednisolone. CONCLUSION: These results suggest that upregulation of the tenascin-C expression is specific to AD lesions, and that tenascin-C may therefore play a critical role in regulating the underlining inflammatory processes, which are involved in the pathology of AD.     

Immunomodulatory effects of ultraviolet B irradiation on atopic dermatitis in NC/Nga mice

BACKGROUND: Atopic dermatitis (AD) is a common pruritic inflammatory skin disease, which occurs primarily in childhood. Recently, narrow-band ultraviolet B (UVB) phototherapy has been used to treat AD, but the mechanism involved is unknown. In this study, we investigated whether UVB irradiation influences AD in the NC/Nga mouse. METHODS: The mice were separated into three groups: control, AD-control (immunized with mite antigens), and AD+UVB-irradiated (immunized with mite antigens and UVB irradiation) groups. The mice in the irradiation group were exposed to 1 kJ/m(2)/day twice a week from 6 to 12 weeks of age. Animals in the control and AD-control groups were shaved, but not irradiated. RESULTS: In the AD+UVB-irradiated group, the atopy score, ear thickness, and total immunoglobulin E (IgE) were increased in comparison with the AD-control group. On day 40, the levels of interleukin (IL)-4, IL-5, and IL-10 in the spleen lymphocytes were significantly increased compared with the AD-control group, resulting in a marked decrease of the interferon (IFN)-gamma/IL-4 ratio compared with the AD-control group. In addition, the levels of IL-6, tumor necrosis factor (TNF)-alpha, and NO(x) production by peritoneal macrophages were significantly elevated. CONCLUSION: These results indicate that UVB irradiation promotes the development of AD-like skin lesions in NC/Nga mice.     

Gene expression of enzymes for tryptophan degradation pathway is upregulated in the skin lesions of patients with atopic dermatitis or psoriasis

BACKGROUND: Atopic dermatitis (AD) and psoriasis are common inflammatory skin diseases. Although many reports implicate Th2 cytokines in the pathophysiology of AD and Th1 cytokines in psoriasis, the precise etiology of these diseases remains elusive. OBJECTIVE: We investigated novel AD- or psoriasis-related genes to further understand the pathogenesis of these diseases. METHODS: We performed a comprehensive analysis of mRNA expression in skin biopsies from AD or psoriasis patients using DNA microarrays. Quantitative PCR was then used to monitor the expression of novel disease-related genes in human keratinocytes or pinnae from NC/Nga mice. RESULTS: Levels of mRNA for IDO (indoleamine 2,3-dioxygenase) and kynureninase, enzymes constituting the tryptophan degradation pathway, were found to be upregulated in the skin lesions as compared to the uninvolved skin of patients with AD or psoriasis. Expression of these two genes was induced in human epidermal keratinocytes stimulated with IFN-gamma in vitro. Moreover, in NC/Nga mice, the expression of kynureninase mRNA in the ear skin was induced following development of AD-like skin lesions. CONCLUSION: The tryptophan degradation pathway may play an important role in the pathophysiology of AD and psoriasis.     

Role of scratch-induced cutaneous prostaglandin D production on atopic-like scratching behaviour in mice

NC/Nga mice are known to develop scratching dermatitis akin to atopic dermatitis, under conventional (Conv), but not under the specific-pathogen-free (SPF) condition. In this study, we examined the effects of mechanical-scratching on the spontaneous scratching counts (sign of itching), in relation to the cutaneous prostaglandin D2 (PGD2) levels in NC/Nga or BALB/c mice. Mechanical-scratching increased the cutaneous barrier damage and PGD2 levels in both strain mice under the SPF condition. By 4 weeks of cohabitation with the skin-lesioned NC/Nga mice, both the increase in the spontaneous scratching and development of dermatitis score were higher in the Conv-NC/Nga than in the Conv-BALB/c mice. At this time-point, the cutaneous PGD2 level induced by mechanical-scratching was significantly lower in the Conv-NC/Nga when compared with that in the SPF-NC/Nga mice, and that in the Conv-BALB/c was almost equal to that in the SPF-BALB/c mice. With mechanical scratches, the cohabitation-induced scratching was suppressed in the Conv-BALB/c, but not in the Conv-NC/Nga mice. These results suggest that the scratch-induced cutaneous PGD2 inhibits scratching and the subsequent development of dermatitis in BALB/c, while the impaired scratch-induced cutaneous PGD2 production in the NC/Nga mice resulted in no suppression of scratching, and aggravated the dermatitis.     

Semaphorin3A alleviates skin lesions and scratching behavior in NC/Nga mice, an atopic dermatitis model

Topical steroids and antihistamines are commonly used for the treatment of atopic dermatitis (AD). However, in a substantial number of patients with AD, these treatments are not sufficiently effective. In AD patients, C-fibers in the epidermis increase and sprout, inducing hypersensitivity, which is considered to aggravate the disease. Semaphorin3A (Sema3A), an axon guidance molecule, is a potent inhibitor of neurite outgrowth of sensory neurons. To investigate the effect of Sema3A on AD, we administered recombinant Sema3A intracutaneously into the skin lesions of NC/Nga mice, an animal model of AD. Sema3A dose-dependently improved skin lesions and attenuated the scratching behavior in NC/Nga mice. Histological examinations revealed a decrease in: (a) epidermal thickness; (b) the density of invasive nerve fibers in the epidermis; (c) inflammatory infiltrates, including mast cells and CD4+ T cells; and (d) the production of IL-4 in the Sema3A-treated lesions. Because the interruption of the itch-scratch cycle likely contributes to the improvement of the AD-like skin lesions, Sema3A is promising in the treatment of patients with refractory AD, as well as overall itching dermatosis.     

Adipose‐derived stem cells attenuate atopic dermatitis‐like skin lesions in NC/Nga mice

There is an unmet need in novel therapeutics for atopic dermatitis (AD). We examined the effects of autologous adipose‐derived stem cells (ADSCs) on AD‐like skin lesions induced by the application of 2,4‐dinitrochlorobenzene (DNCB) in NC/Nga mice. Autologous ADSCs and ADSC‐conditioned medium (ADSC‐CM) were injected intralesionally three times. Clinical severity and histopathologic findings were compared in sham naïve control, saline‐treated, ADSC‐treated, ADSC‐CM‐treated and 2.5% cortisone lotion‐applied animals. The severity index, skin thickness, mast cell number, as well as expression levels of thymic stromal lymphopoietin, CD45, chemoattractant receptor‐homologous molecule, chemokine ligand 9 and chemokine ligand 20 were significantly lower in mice treated with ADSC, ADSC‐CM, or 2.5% cortisone lotion. Tissue levels of interferon‐γ as well as serum levels of interleukin‐33 and immunoglobulin E levels were also decreased in those groups. We conclude that autologous ADSCs improved DNCB‐induced AD‐like skin lesions in NC/Nga mice by reducing inflammation associated with Th2 immune response and interferon‐γ.     

Suppression of spontaneous dermatitis in NC/Nga murine model by PG102 isolated from Actinidia arguta

Atopic dermatitis (AD) is a chronic inflammatory skin disease, which requires safe and effective pharmacological therapy. We previously found that two preparations from Actinidia arguta, PG102T, and PG102E, could modulate Th1/Th2 pathways and suppress IgE biosynthesis. This study was performed to assess the therapeutic effects of PG102T and PG102E on the development of dermatitis in NC/Nga mice, characterized by the spontaneous onset of AD along with an elevated level of IgE under conventional conditions. PG102T or PG102E administration significantly reduced dermatitis severity as well as scratching tendency in conventional mice. The suppression of dermatitis by PG102 was accompanied by a decrease in the plasma level of IgE, IgG1, and IL-4 and also by an increase in that of IgG2a and IL-12. The splenic level of IL-4, IL-5, and IL-10 was downregulated, whereas that of IFN-gamma and IL-12 was increased. The number of eosinophils and the expression of eotaxin and thymus and activation-regulated chemokine were decreased by PG102T or PG102E. Histological findings also indicated that the thickening of epidermis/dermis and the dermal infiltration of inflammatory cells including mast cells were greatly inhibited. These data suggest that PG102 may be effective therapeutic agents for the treatment of AD.     

Impairment of skin barrier function in NC/Nga Tnd mice as a possible model for atopic dermatitis

BACKGROUND: The pathogenesis and aetiology of atopic dermatitis (AD) remain unclear. Establishment of suitable animal models should aid elucidation of the pathogenesis and development of therapy. OBJECTIVES: We focused on biophysical and biochemical parameters in the skin of NC/Nga Tnd mice to evaluate similarities to and differences from AD. METHODS: Biophysical (transepidermal water loss and skin surface conductance) and biochemical parameters (ceramide contents and activity of ceramide-metabolizing enzymes) were measured in NC/Nga Tnd mice in which spontaneous dermatitis appeared under ambient laboratory conditions (ALC). RESULTS: Biophysical parameters suggested impairment of water retention properties and barrier function. The amount of ceramide in NC/Nga Tnd mice under ALC decreased significantly. These dermatological features resembled those of AD, as did the clinical signs and histological changes. CONCLUSIONS: The results described here and previous immunological studies on AD suggest that the NC/Nga Tnd mouse may be a suitable model for certain aspects of AD.