A Mouse Ear Model for Allergic Contact Dermatitis Evaluation

Summary

Here, we describe the methods for inducing allergic contact dermatitis in mouse ears by 1-fluoro-2,4-dinitrobenzene (DNFB) and how to evaluate the severity of allergic contact dermatitis.

Abstract

Skin is the human body's first line of defense and one of the most exposed organs to environmental chemicals. Allergic contact dermatitis (ACD) is a common skin disease that manifests as a local rash, redness, and skin lesions. The occurrence and development of ACD are influenced by both genetic and environmental factors. Although many scholars have constructed a series of models of ACD in recent years, the experimental protocols of these models are all different, which makes it difficult for readers to establish them well. Therefore, a stable and efficient animal model is of great significance to further study the pathogenesis of atopic dermatitis. In this study, we detail a modeling method using 1-fluoro-2,4-dinitrobenzene (DNFB) to induce ACD-like symptoms in the ears of mice and describe several methods for assessing the severity of dermatitis during modeling. This experimental protocol has been successfully applied in some experiments and has a certain promotional role in the field of ACD research.

Introduction

Allergic contact dermatitis (ACD) is a common skin disease that is characterized by eczema-like symptoms at the contact site, edema and erythema in moderate cases, and papules, erosion, exudation, or even massive scars in severe cases¹. It affects up to 20% of the population and can affect people of any age². ACD often occurs in individuals who have been exposed to allergens repeatedly and can be caused by the individual's immune response to one or more allergens in their home or workplace³. Type IV delayed hypersensitivity is considered the main type of immune response i....

Protocol

All the care and treatment of the mice were in accordance with the guidelines established by the Institutional Animal Care and Use Committee of Yangzhou University and were approved by the Institutional Animal Care and Use Committee under the project license SYXK(SU)2022-0044. BALB/c male and female mice aged 6-8 weeks were used in this study. Each group consisted of six mice (see Table of Materials). Cages were placed in a temperature-controlled chamber (22 ± 2 °C, 12 h light/dark cycle) with free access to food and water. An experimental flow diagram is shown in Figure 1.

1. A....

Results

Under repeated DNFB stimulation, the mouse ears of the DNFB group displayed evident clinical symptoms comparable to ACD, with sensitive areas showing the typical symptoms of redness, dryness, and even erosion and exudation. However, ear administration of pure water (control group) or solvent control (vehicle group) did not produce similar symptoms (Figure 4).

Meanwhile, in the DNFB group, compared to the untreated right ear, the thickness of the left ear increased.......

Discussion

The protocol described here for inducing ACD-like symptoms in the ears of mice can be used to study the pathophysiology of ACD and as a screening tool for the development of new drugs.

There are two key steps to establish an ACD model: initial sensitization, and subsequent stimulation. The abdomen is usually the site of initial sensitization, but the subsequent stimulation site was chosen slightly differently. Previous studies have shown that most scholars choose to use chemical sensitizers su.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
1-Fluoro-2,4-dinitrobenzene (DNFB)	Merck	200-734-3	1-Fluoro-2,4-dinitrobenzene, ≥99%
Acetone	Sinopharm Chemical Reagent Co. LTD	10000418	≥99.5%
Aluminum foil	Cleanwrap	CF-2
Evans blue dye	Solarbio	314-13-6	Dye content approx. 80%
Mouse fixator	ZHUYANBANG	GEGD-SM1830
Olive oil	Solarbio	8001-25-0	500 ml
Pipet tip	Biofount	FT-200	10 - 200 μl
Pipettor	Eppendorf AG	3123000250	20 - 200 μl
Razor blade	Shanghai Gillette Co. LTD	74-S
Vernier calipers	Delixi Electric	DECHOTVCS1200