Ann Dermatol.  2016 Dec;28(6):690-696. 10.5021/ad.2016.28.6.690.

Application of Topical Acids Improves Atopic Dermatitis in Murine Model by Enhancement of Skin Barrier Functions Regardless of the Origin of Acids

• Lee NR
• Lee HJ
• Yoon NY
• Kim D
• Jung M
• Choi EH

• KMID: 2368118
• DOI: http://doi.org/10.5021/ad.2016.28.6.690

Abstract

BACKGROUND
The acidic pH of the stratum corneum (SC) is important for epidermal permeability barrier homeostasis. Acidification of the skin surface has been suggested as a therapeutic strategy for skin disorders such as atopic dermatitis (AD).
OBJECTIVE
We performed an animal study to evaluate the usefulness of acidification of SC for inhibition of AD lesions and to find out if the therapeutic effect of vinegar is attributable to its herbal contents, rather than its acidity.
METHODS
Five groups of six oxazolone-treated (Ox)-AD mice were treated for three weeks with creams of different acidity: vehicle cream alone (pH 5.5), neutralized vinegar cream (pH 7.4), pH 5.0 vinegar cream, pH 3.5 vinegar cream, and pH 3.5 hydrogen chloride (HCl) cream. Also, we have compared two groups of Ox-AD mice treated with pH 5.5 vehicle cream or pH 5.5 vinegar cream.
RESULTS
Ox-AD mice treated with acidic creams exhibited fewer AD-like lesions, had significantly lower eczema scores, decreased basal by transepidermal water loss (TEWL), and increased SC hydration compared to the groups given only vehicle and neutral cream. There was no significant difference between the acidic vinegar and HCl groups. Between the groups treated with vehicle and pH 5.5 vinegar cream, there was no difference in eczema score, basal TEWL and SC hydration.
CONCLUSION
Application of topical acids, regardless of their source materials, inhibits the development of AD lesions by maintenance of skin surface pH and skin barrier function in murine model.

Keyword

Atopic dermatitis; Skin barrier; Skin pH; Topical acid; Vinegar

MeSH Terms

Acetic Acid
Animals
Dermatitis, Atopic*
Eczema
Homeostasis
Hydrochloric Acid
Hydrogen-Ion Concentration
Mice
Permeability
Skin*
Water
Acetic Acid
Hydrochloric Acid
Water

Figure

• 

  Fig. 1 (A) Oxazolone-treated atopic dermatitis (Ox-AD) mice groups treated with pH 3.5 vinegar cream, pH 5.0 vinegar cream, or pH 3.5 hydrogen chloride (HCl) cream exhibited fewer AD-like lesions than mice treated with only vehicle cream (pH 5.5) or neutralized vinegar cream (pH 7.4). (B) Eczema scores were significantly higher in the vehicle group than in the acidic cream treatment groups. There was no difference in the eczema scores between vehicle group and neutralized vinegar cream treated group. Eczema scores were determined by the sum of the severity of erythema, edema, and lichenification. Severity: absent (0), mild (1), moderate (2), and severe (3). Results are shown as the mean±standard error of the mean. **p<0.05, ***p<0.001.

• 

  Fig. 2 (A, B) Significant decreases in basal transepidermal water loss (TEWL) and significant increases in stratum corneum (SC) hydration were observed in the mouse groups treated with pH 3.5 hydrogen chloride (HCl) cream or pH 3.5 and 5.0 vinegar creams compared with vehicle (veh.) or neutralized vinegar (neut vin.) cream. No significant differences were seen between the acidic vinegar-treated and HCl-treated group. Results are shown as the mean±standard error of the mean.

• 

  Fig. 3 (A) Eczema scores and (B) skin permeability barrier functions of Ox induced AD model mice after application of vehicle and pH 5.5 vinegar creams. Ox: oxazolone-treated, AD: atopic dermatitis, TEWL: transepidermal water loss, SC: stratum corneum.

• 

  Fig. 4 Maintenance of acidic pH after application of pH 3.5 vinegar, pH 3.5 hydrogen chloride (HCl) and pH 5.0 vinegar cream. Immediately after application of acidic cream, the skin surface pH decreased in pH 3.5 vinegar cream and HCl cream but not in pH 5.0 vinegar cream. Although pH rised after 15 minutes, the slope of increase was gentle, therefore low pH was maintained throughout 6 hours after application of acidic creams.

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