Objective

2

To investigate the therapeutic effect and possible mechanism of four types of Chinese herbal moisturizers made in laboratory for atopic dermatitis induced by 2，4-dinitrofluorobenzene （DNFB） in mice.

Method

2

According to the body weight， BALA/c mice were randomly divided into normal group， model group， blank cream group （moisturizer A）， Shaoyao Gancaotang group （moisturizer B）， Shaoyao Gancaotang with Portulacae Herba，Ginseng Radix et Rhizoma and Honeysuckle Stem group （moisturizer C）， and Shaoyao Gancaotang with Ginseng Radix et Rhizoma and Honeysuckle Stem group （moisturizer D） ， with the dose of 25 g·kg

-1

per day， as well as tacrolimus ointment group of 3 g·kg

-1

per day， with 10 to 12 mice in each group. Except the normal group， the mice in the other groups were treated with 0.5% DNFB in the hair removal skin of back， 100 μL each for 7 days. Starting from the 7

th

day， each group was given the appropriate skin cream for external use intervention， once per day， for 15 consecutive days， except for the normal and the model groups. The animal body mass was measured once a week， and the animal back skin was graded three times a week， and the skin lesion score was recorded. After the mice were killed， the left and right ears were taken， the weight of both ears was punched and the degree of swelling was calculated. The back skin was fixed and stained with hematoxylin-eosin（HE） method， and then pathologic examination was conducted to observe and score the pathological changes of mouse back skin. Blood was obtained after the last dose and enzyme-linked immunosorbent assay （ELISA） was used to determine the immunoglobulin（Ig）E content in serum. Western blot was used to measure the expression of signal transduction and activator of transcription 3 （STAT3）， phosphorylation （p）-STAT3 in the skin tissue.

Result

2

Compared with the normal group， the body mass decreased continuously， a series of inflammatory changes such as erythema， edema， dryness， desquamation and callus exfoliation and so on occurred in the modeling area， and the skin lesion score increased significantly in the model group. Additionally， the cuticle of ear skin was thickened and the degree of ear swelling was obviously increased in the model group. Microscopically， the occurred changes in the model mice included the local necrosis of the epidermis， epidermal thickening， epidermal hyperplasia， and the hyperkeratosis and hypokeratosis in the cuticle， as well as the subcutaneous inflammatory cell infiltration and so on. Furthermore， the content of serum IgE andthe expression of p-STAT3 in skin tissues increased significantly in the model group. Compared with the model group， the body mass of mice in group C and D was significantly increased （

P

<

0.01）， and the skin lesion status score was decreased （

P

<

0.05，

P

<

0.01）.The degree of auricle swelling was significantly reduced in group B， C and D compared with that in the model group （

P

<

0.01）.The degree of skin necrosis and defect and epidermal hyperplasia of mice in moisturizer C group was significantly reduced compared with that in model group （

P

<

0.05，

P

<

0.01）. Serum IgE levels of mice in group C and D were significantly lower than those in the model group （

P

<

0.05，

P

<

0.01）. The expression of p-STAT3 protein in skin tissues of mice in moisturizer C group was significantly lower than that in model group （

P

<

0.05）.

Conclusion

2

The moisturizers B， C and D all have certain therapeutic effect on atopic dermatitis， among which moisturizers C has the most obvious therapeutic effect. The possible mechanism may be that it reduces the level of inflammatory cytokines by inhibiting the increase of serum IgE content and the phosphorylation of STAT3.