Atopic Dermatitis Mouse Model Introduction
- Atopic dermatitis (AD) is a chronic skin disease that presents with itching, erythema and squamous lesions, and can be associated with cardiovascular disease, mental disorders (depression, anxiety, sleep disorders, etc.) and other diseases.
- Atopic dermatitis mouse models:
- Induced by enhanced skin sensitization using epithelial sensitive antigens, haptens, etc.
- Genetically engineered atopic dermatitis mouse model;
- Spontaneous atopic dermatitis mouse model.
- Biocytogen uses wild-type C57BL/6 mice and B-hIL4/hIL4RA double humanized mice on the C57BL/6 background to experimentally induce AD-like lesions via oxazolone (OXA) sensitization and continuous challenge. The resulting atopic dermatitis mouse model can be used for preclinical efficacy evaluation of therapeutic candidates.
Watch our December 2021 webinar: Investigating Inflammatory Disease using Humanized Cytokine Mice
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Atopic Dermatitis Model Induction
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Experimental mouse strains: C57BL/6, BALB/c, 5-6 weeks old, female
Modeling reagent: OXA
Modeling method: Sensitization, day 0; Challenge, day 7-25
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Clinical Assessment and Total Serum IgE Levels
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Atopic dermatitis was chemically induced in wild-type C57BL/6 mice by OXA sensitization and continuous challenge. (A) Body weight, (B) ear thickness, and (C) total serum IgE concentrations were measured in wild-type C57BL/6 mice exposed to vehicle control or OXA.
Ear thickness and serum IgE levels were significantly increased in wild-type C57BL/6 mice treated with OXA compared to vehicle control.
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Pathologic Assessment
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Ear skin pathology and lymphocyte infiltration analysis in a wild-type C57BL/6 atopic dermatitis mouse model. (A) Hematoxylin and eosin (H&E) staining of mouse ear tissue sections, and (B) eosinophil infiltration scores of the ear epidermis.
Wild-type C57BL/6 OXA-treated mice displayed varying degrees of stromal cell proliferation, thickening, hyperkeratosis with hypokeratosis, crust, mixed inflammatory cell infiltration in dermis and subcutaneous tissue and other atopic dermatitis-related pathological changes in the epidermis. Additionally, wild-type C57BL/6 OXA-treated mice had a significantly higher eosinophil infiltration score compared to wild-type C57BL/6 vehicle control-treated mice. These combined results demonstrate that wild-type C57BL/6 OXA-treated mice successfully induce atopic dermatitis-like pathology.
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Dexamethasone Efficacy Analysis in Wild-Type-AD Mice
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Efficacy of dexamethasone (Dex) was confirmed in a wild-type C57BL/6 atopic dermatitis mouse model. (A) Mouse body weight, (B) ear thickness, and (C) total serum IgE levels were measured in wild-type C57BL/6 mice exposed to vehicle control (G1), OXA alone (G2), or in combination with increasing concentrations of dexamethasone (G3-G5) as indicated in the dosing regimen (twice/week).
Our results indicate that dexamethasone treatment significantly reduced ear thickness compared to wild-type C57BL/6 OXA-only mice. In particular, high dose of dexamethasone (0.09% Dex) in wild-type C57BL/6 OXA-treated mice completely relieved ear skin edema comparable to that of control levels, however it was also associated with significant weight loss compared to the control group. Lastly, medium and high doses of dexamethasone (0.06%, 0.09%) in wild-type C57BL/6 OXA-treated mice reduced the concentration of total serum IgE levels.
Efficacy of dexamethasone (Dex) was confirmed in a wild-type C57BL/6 atopic dermatitis mouse model. (A) Hematoxylin and eosin (H&E) staining of mouse ear tissue sections, and (B) eosinophil infiltration scores of the ear epidermis in wild-type C57BL/6 mice exposed to vehicle control (G1), OXA alone (G2), or in combination with increasing concentrations of dexamethasone (G3-G5) as indicated in the dosing regimen (twice/week).
Our results indicate that pathological changes related to atopic dermatitis, such as stromal cell proliferation, thickening, and mixed inflammatory cell infiltration were observed in the ear epidermis of wild-type C57BL/6 OXA-treated mice (G2). These observed phenotypes were significantly alleviated with dexamethasone administration in wild-type C57BL/6 OXA-treated mice(G3-G5) compared to OXA-alone, especially with high dose of dexamethasone (0.09%). Additionally, the eosinophil infiltration score in the ear epidermis was significantly lower with dexamethasone treatment. Overall, dexamethasone improved atopic dermatitis-related symptoms most notably at concentrations of 0.06% and 0.09%. These combined results indicate that the atopic dermatitis mouse model can be chemically induced by OXA and is a powerful tool for efficacy evaluation.
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Human IL4 and IL4RA Expression in Humanized B-hIL4/hIL4RA Mice
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Species-specific IL4 and IL4RA expression in homozygous humanized B-hIL4/hIL4RA mice. Following anti-CD3ɛ stimulation in vivo, (A) serum was collected from wild-type C57BL/6 (+/+) and homozygous B-hIL4/hIL4RA (H/H) mice and analyzed using a species-specific IL4 ELISA kit, while (B) splenocytes were isolated from wild-type C57BL/6 (+/+) and homozygous B-hIL4/hIL4RA (H/H) mice and analyzed by flow cytometry using a species-specific anti-IL4RA antibody.
These results suggest human IL4 and IL4RA is exclusively expressed in humanized B-hIL4/hIL4RA mice compared to wild-type C57BL/6 mice.
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In Vivo Anti-Human IL4RA Antibody Efficacy Evaluation Using Humanized B-hIL4/hIL4RA-AD Mice
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Anti-human IL4RA antibody efficacy was confirmed in humanized B-hIL4/hIL4RA mice with atopic dermatitis. (A) Mouse body weight, (B) ear thickness, and (C) total serum IgE levels were measured in humanized B-hIL4/hIL4RA mice exposed to vehicle control (G1), OXA-hIgG control (G2), or OXA in combination with increasing concentrations of an anti-human IL4RA antibody analog (dupilumab, G3-G6) as indicated in the dosing regimen (twice/week).
Our results indicate that dupilumab treatment improved ear thickness compared to B-hIL4/IL4RA OXA-hIgG treated mice. Additionally, high concentrations of dupilumab (25 mg/kg) in B-hIL4/IL4RA OXA-treated mice reduced the concentration of serum total IgE levels, altogether suggesting that ear thickness and total IgE levels are inversely correlated with dupilumab dose.
Efficacy of anti-human IL4RA antibody on skin and lymphocyte infiltration in the ear of B-hIL4/hIL4RA mice with experimental atopic dermatitis. (A) Hematoxylin and eosin (H&E) staining of mouse ear tissue sections, and (B) eosinophil infiltration scores of the ear epidermis in B-hIL4/hIL4RA mice exposed to vehicle control (G1), OXA-hIgG control (G2), or OXA in combination with increasing concentrations of an anti-human IL4RA antibody analog (dupilumab, G3-G6) as indicated in the dosing regimen (twice/week).
Our results indicate that pathological changes related to atopic dermatitis, such as stromal cell proliferation, thickening, and mixed inflammatory cell infiltration were observed in the ear epidermis of B-hIL4/hIL4RA OXA-hIgG treated mice (G2). These observed phenotypes were significantly alleviated with dupilumab administration in B-hIL4/hIL4RA OXA-treated mice (G3-G6) compared to OXA-hIgG, especially with high doses of dupilumab (25 mg/kg). Additionally, the eosinophil infiltration score in the ear epidermis was significantly lower with high doses of dupilumab treatment. Overall, dupilumab improved atopic dermatitis-related symptoms in B-hIL4/hIL4RA OXA-treated mice, indicating that B-hIL4/hIL4RA mice are a powerful preclinical model for in vivo efficacy evaluation of anti-human IL4RA antibodies.
