Mouse Model of Irritant Contact Dermatitis

Background

Irritant contact dermatitis is a common inflammatory skin disease characterized by skin barrier dysfunction, eczematous dermatitis, and chronic itching. This disease severely affects the quality of life. Considering that the current treatment approaches are not ideal, more extensive research is needed to develop new treatments. Mainly, a mouse model is needed to investigate the effectiveness of new drugs to treat this disease.

Objectives

This study was conducted to create a mouse model of irritant contact dermatitis.

Methods

In the current study, we used BALB/c female mice to prepare a mouse model of irritant contact dermatitis. To induce irritant contact dermatitis, we used a dinitrochlorobenzene mixture with acetone/olive oil as an irritant. After 10 days of application, the mouse skin tissue was isolated and examined in terms of histopathology.

Results

The introduced protocol created an irritant contact dermatitis model clinically and histopathologically.

Conclusions

In the present study, we introduced a new protocol using a mixture of dinitrochlorobenzene and acetone/olive oil to create an irritant contact dermatitis model. Mouse models have been extensively used to discover the complex mechanisms of irritant contact dermatitis and provide a preclinical platform before conducting clinical interventional research on humans to evaluate a new therapeutic approach. However, one should always look for models that cause the least pain and suffering in the animal and simultaneously are simple and reliable for the desired studies. Thus, our protocol is a new approach that can be effective and painless in creating a model of irritant contact dermatitis.

Use of Contact Immunotherapy in the Treatment of Skin Diseases Other than Alopecia Areata

For decades, contact immunotherapy with dinitrochlorobenzene, diphencyprone, and squaric acid dibutylester has played an important role in both clinical practice and scientific research. It is listed as the first-line treatment for extensive alopecia areata and was more recently approved for melanoma treatment as an orphan drug in the USA. Moreover, owing to the relative low cost and safety, topical immunotherapy has also been used in many infectious, neoplastic, and inflammatory dermatological diseases. It is especially valuable in vulnerable groups, for cosmetic/pain sensitive areas, or for multiple lesions. In this review, we summarize the current evidence supporting the use of contact immunotherapy for treatment of skin diseases, from articles collected from PubMed database. Owing to space limitation and already numerous studies focusing on alopecia areata, we include only skin diseases other than alopecia areata. In addition to diseases that have been reported to be treated by contact immunotherapy, the hypothesized mechanism, prognosis prediction, efficacy, and safety of these topical agents are discussed.

In vitro co-culture model of human monocyte-derived dendritic cells and T cells to evaluate the sensitization of dinitrochlorobenzene

Exposure to sensitizer has been suggested to be hazardous to human health, evaluation the sensitization of sensitizer is particularly important and urgently needed. Dendritic cells (DCs) exert an irreplaceable function in immunity, and the T cell receptor (TCR) repertoire is key to ensuring immune response to foreign antigens. We hypothesized that a co-culture model of human monocyte-derived dendritic cells (Mo-DCs) and T cells could be employed to evaluate the sensitization of DNCB. An experimental model of DNCB-induced sensitization in rat was employed to examine alterations of cluster of differentiation CD103⁺ DCs and T cells. A co-cultured model of Mo-DCs and T cells was developed in vitro to assess the sensitization of DNCB through the phenotypic and functional alterations of Mo-DCs, as well as the TCR repertoire. We found that the CD103⁺ DCs phenotype and T-helper (Th) cells polarization altered in sensitization rats. In vitro, phenotypic alteration of Mo-DCs caused by DNCB were consistent with in vivo results, antigen uptake capacity of Mo-DCs diminished and capacity of Mo-DCs to prime T cell increased. Clones of the TCR repertoire and the diversity of TCR repertoire were enhanced, changes were noted in the usage of variable, joining, and variable-joining gene combinations. DNCB exposure potentiated alterations and characteristics of Mo-DCs and the TCR repertoire in a co-culture model. Such changes provided innovative ideas for evaluating sensitization of DNCB.

Effects of mineral complex material treatment on 2,4- dinitrochlorobenzene-induced atopic dermatitis like-skin lesions in mice model

Background

Atopic dermatitis (AD) is a chronic allergic inflammatory skin disease characterized by complex pathogenesis including skin barrier dysfunction, immune-redox disturbances, and pruritus. Prolonged topical treatment with medications such as corticosteroids, calcineurin inhibitors, and T-cell inhibitors may have some potential side-effects. To this end, many researchers have explored numerous alternative therapies using natural products and mineral compounds with antioxidant or immunomodulatory effects to minimize toxicity and adverse-effects. In the current study, we investigated the effects of mineral complex material (MCM) treatment on 2, 4-dinitrochlorobenzene (DNCB)-induced AD-like skin lesions in SKH-1 hairless mice.

Methods

Animals were divided into four groups; normal control (NC), negative control treated with DNCB only (DNCB only), positive control treated with DNCB and tacrolimus ointment (PC) and experimental group treated with DNCB and MCM patch (MCM). Skin inflammation and lesion severity were investigated through analyses of skin parameters (barrier score and strength, moisture and trans-epidermal water loss level), histopathology, immunoglobulin E, and cytokines. In addition, reactive oxygen species (ROS), nitric oxide (NO), glutathione peroxidase (GPx), and catalase (CAT) levels were measured in both serum and skin lysate.

Results

Our results demonstrates that MCM patch improved the progression of AD-like skin lesions by significantly increasing skin barrier strength and decreasing trans-epidermal water loss. Additionally, dermal administration of MCM patch significantly reduced epidermal thickness, ROS, and NO levels in skin lysate. Furthermore, we found that MCM suppressed the levels of AD-involved (Th₁ and Th₂) cytokines such as IL-2, IFN-γ, and IL-4 in blood. In addition, the levels of other Th_1, and Th₂ and inflammatory cytokines such as IL-1β, TNF-α, IL-6, IL-12(p70) and IL-10 were found lowest in the MCM group than in the DNCB only and PC groups. Moreover, we found total serum IgE level significantly increased after DNCB treatment, but decreased in the PC and MCM groups.

Conclusion

Taken together, our findings suggest that MCM application may have beneficial effects either systemic or regional on DNCB-induced AD lesional skin via regulation of the skin barrier function and immune-redox response.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-021-03259-5.

Jageum-Jung improves 2,4-dinitrochlorobenzene-induced atopic dermatitis-like skin lesions in mice and suppresses pro-inflammatory chemokine production by inhibiting TNF-α/IFN-γ-induced STAT-1 and NFκB signaling in HaCaT cells

ETHNOPHARMACOLOGICAL RELEVANCE

Jageum-Jung (JGJ) is an oriental herbal formula comprising five herbs (Melaphis chinensis Bell, Cremastra variabilis Nakai, Knoxia valerianoides Thorel, Euphorbia lathyris L., and Moschus moschiferus L.). It has been used for detoxification and treating cancer and inflammatory diseases in China, Japan, and Korea. However, the mechanism of action of JGJ on keratinocyte inflammatory response is poorly understood.

AIM OF THE STUDY

In the present study, we investigated the anti-inflammatory mechanism of JGJ and studied the effects of JGJ on atopic dermatitis-like skin lesions in mice.

MATERIALS AND METHODS

We elucidated the anti-inflammatory and anti-inflammatory effects of JGJ on tumor necrosis factor-α/interferon-γ (TNF-α/IFN-γ)-treated human keratinocyte cells, IgE-sensitized RBL-2H3 cells, and 2,4-dinitrochlorobenzene (DNCB)-induced atopic dermatitis (AD)-like mice, respectively.

RESULTS

The results showed that JGJ suppressed the production and mRNA revels of IL-8, IL-6 and, conspicuously, both TARC and RANTES. JGJ inhibited nuclear translocation of the inflammatory transcription factors NFκB and STAT-1. Moreover, JGJ improved AD-like skin lesions in DNCB-treated mice and inhibited degranulation of mast cell.

CONCLUSIONS

The results of this study suggest that JGJ can be considered as a candidate agent for AD treatment.

Oral warfarin intake affects skin inflammatory cytokine responses in rats

Warfarin is an anticoagulant used in prevention/prophylaxis of thromboembolism. Besides the effects on coagulation, non-hemorrhagic reactions have also been documented. Although cutaneous reactions were reported in some patients, the impact on skin immunity was not explored. In the present paper, the effect of 30-day oral warfarin intake on skin cytokine responses in rats was analyzed. Increased release of inflammatory cytokines (TNF, IL-1β and IL-10) was noted by skin explants from rats which received warfarin, but without effect on IL-6. No impact on epidermal cell cytokine secretion was seen, except a tendency of an increase of IL-6 response to stimulation with microbial product lipopolysaccharide (LPS). Topical application of contact allergen dinitrochlorobenzene (DNCB) resulted in slight (numerical solely) increase of TNF release by skin explants of warfarin-treated animals, while epidermal cells responded by increased secretion of all four cytokines examined. The data presented provide new information on the potential of oral warfarin to modulate skin innate immune activity.

NCB-02 (standardized Curcumin preparation) protects dinitrochlorobenzene-induced colitis through down-regulation of NFκ-B and iNOS

AIM: To evaluate the efficacy and mechanism of action of NCB-02, a standardized Curcumin preparation, against 2, 4-dinitrochlorobenzene (DNCB)-induced ulcerative colitis in rats.

METHODS: Ulcerative colitis was induced in male rats by sensitizing with topical application of DNCB in acetone for 14 d and intra-colonol challenge with DNCB on day 15. A separate group of animals with vehicle treatment in similar fashion served as control group. Colitis rats were divided into different groups and treated with NCB-02 at doses of 25, 50 and 100 mg/kg b.wt p.o. for 10 d. Sulfasalazine at a dose of 100 mg/kg b.wt for 10 d served as a reference group. On day 10 after respective assigned treatment, all the animals were euthanized and the length of the colon, weight of entire colon and distal 8 cm of the colon were recorded. The distal part of the colon was immediately observed under a stereomicroscope and the degree of damage was scored. Further distal 8 cm of the colon was subject to the determination of colonic myeloperoxidase (MPO), lipid peroxidation (LPO) and alkaline phosphatase (ALP) activities. A small piece of the sample from distal colon of each animal was fixed in 10% neutral buffered formalin and embedded in paraffin wax and sectioned for immunohistochemical examination of NFκ-B and iNOS expression.

RESULTS: NCB-02 showed a dose dependent protection against DNCB-induced alteration in colon length and weight. NCB-02 treatment also showed a dose dependent protection against the elevated levels of MPO, LPO and ALP, induced by DNCB. NCB-02 demonstrated a significant effect at a dose of 100 mg/kg b.wt., which was almost equipotent to 100 mg/kg b.wt. of sulfasalazine. Treatment with sulfasalazine and curcumin at a dose of 100 mg/kg b.wt. inhibited the DNCB-induced overexpression of NFκ-B and iNOS in the colon.

CONCLUSION: Curcumin treatment ameliorates colonic damage in DNCB-induced colitic rats, an effect associated with an improvement in intestinal oxidative stress and downregulation of colonic NFκ-B and iNOS expression.