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DNCB-Induced Atopic/Contact Dermatitis Rat Model

Background
The DNCB-induced rat dermatitis model is a classic chemically sensitized dermatitis model widely used in skin pharmacology and allergic skin disease research for simulating clinical allergic contact dermatitis, chronic eczema and atopic dermatitis. As a strong hapten sensitizer, 2,4-dinitrochlorobenzene (DNCB) penetrates the skin and binds to cutaneous tissue proteins to form complete antigens, triggering specific immune sensitization. After primary sensitization and repeated topical challenge, DNCB persistently activates mixed Th2/Th1 cutaneous inflammatory responses, destroys skin barrier integrity, and induces typical dermatitis lesions including erythema, papules, edema, scaling, crusting, skin hypertrophy and severe pruritus. With clear pathogenesis, strong sensitization and excellent reproducibility, this model stably mimics clinical delayed-type hypersensitivity, skin barrier damage and chronic recurrent skin inflammation, serving as a standard model for screening anti-inflammatory, anti-pruritic and barrier-repairing drugs. DNCB-induced rat dermatitis model，2,4-dinitrochlorobenzene skin inflammation model，allergic contact dermatitis rat model
Materials and methods
SPF-grade SD or Wistar rats aged 6–8 weeks with body weight of 180–220 g are used. Male rats are preferred due to stable hormone levels and uniform dermatitis phenotypes. All rats are housed in an SPF barrier system with constant temperature and humidity, 12 h light/dark cycle, and ad libitum access to food and water. After one week of adaptive feeding, formal modeling is initiated with strictly controlled exogenous allergen interference.
Test and verify


Modeling Success Criteria


Model rats exhibit significantly increased spontaneous scratching, back-rubbing and restlessness, with aggravated pruritic behaviors day and night and slightly decreased food intake and activity, consistent with typical pruritus-induced stress in dermatitis.


The modeled skin area presents obvious erythema, edema, papules, dry scaling, infiltration, hypertrophy and crusting with partial mild erosion. The skin lesion score is significantly higher than that of the control group, showing rough texture, decreased elasticity and typical chronic recurrent dermatitis characteristics.


HE staining shows epidermal hyperkeratosis, parakeratosis, acanthosis, epidermal proliferation, dermal edema, vasodilation and congestion, and extensive diffuse inflammatory infiltration, which are consistent with typical pathological changes of DNCB-induced allergic contact dermatitis and chronic atopic dermatitis.


The levels of IL-4, IL-6, TNF-α and IgE in skin tissues and serum are significantly upregulated, while the expression of skin barrier proteins (Filaggrin, Loricrin) is decreased, confirming cutaneous immune disorder and barrier damage and verifying successful modeling.


Model Advantages 


 DNCB exhibits stable chemical sensitization with nearly 100% modeling success rate, minor individual differences and excellent reproducibility. This model presents complete dermatitis phenotypes including delayed-type hypersensitivity, skin barrier damage, chronic inflammation and recurrent pruritus. It features simple operation, no surgical intervention and extremely low mortality. Highly consistent with clinical allergic dermatitis and chronic eczema, it is the gold-standard model for screening dermatological preparations, anti-inflammatory, anti-pruritic and skin barrier-repairing drugs.


Research Applications


The DNCB-induced rat dermatitis model is widely used in the research of allergic contact dermatitis, chronic eczema and atopic dermatitis pathogenesis. It is applied to the pharmacodynamic evaluation and target mechanism verification of traditional Chinese medicine compounds, natural products, topical ointments and targeted preparations with anti-inflammatory, anti-allergic, anti-pruritic and skin barrier-repairing effects, serving as a core mainstream model for basic dermatological research and new drug screening.