Objective

2

To investigate the potential mechanisms of

Jiawei Jingqin Decoction

（加味荆芩汤） in the treatment of rosacea.

Methods

2

Fifty 8-week-old female BALB/c mice were randomly divided into normal control group， model group， and

Jiawei Jingqin Decoction

low， medium， and high-dose groups， with 10 mice in each group. Except for the normal control group， mice in the other groups were injected with 40μl of antimicrobial peptide LL-37 at a concentration of 320 μmol/L on the back， repeated once every 12 hours for a total of 4 injections， to induce the rosacea mouse model. The mice in the normal control group were injected with 40 μl of PBS solution at the same time. After successful modeling， the mice in the

Jiawei Jingqin Decoction

low， medium， and high-dose groups were orally administered

Jiawei Jingqin Decoction

at doses of 4.35， 8.71， and 17.42 g/（kg·d） respectively， while the mice in the normal control group and the model group were orally administered 20 ml/（kg·d） of normal saline. All groups were treated once daily for 5 days. The changes in skin lesions were observed， and the erythema area was measured and scored. Skin tissue at the injection site was collected for histopathological examination using HE staining， and the number of mast cells was detected using toluidine blue staining. The levels of interleukin-6 （IL-6）， interleukin-1β （IL-1β）， and tumor necrosis factor-alpha （TNF-α） in the skin lesion tissues were measured using the ELISA method. The mRNA expression levels of key factors in the innate immune response pathway of rosacea disease mechanism， including Toll-like receptor 2 （TLR2）， downstream molecules serine protease kallikrein 5 （KLK5） and matrix metalloproteinase 9 （MMP-9）， as well as related inflammatory factors （IL-1β， IL-6， TNF-α）， and adaptive immune CD4

+

T cell-related factors interferon-gamma （INF-γ） mRNA were detected using RT-qPCR. Immunohistochemical staining was performed to detect the protein expression of KLK5， MMP-9， and the number of CD4

+

T-positive cells. Western blot analysis was used to determine the protein expression levels of CD4

+

T cell-related factors including IFN-γ， CC chemokine receptor 5 （CCR5）， signal transducer and activator of transcription 1 （STAT1）， signal transducer and activator of transcription 3 （STAT3）.

Results

2

The skin at the injection site on the back of mice in the normal control group appeared normal without any skin lesions or erythema， and histopathological examination showed no infiltration of inflammatory cells. The model group had significantly higher erythema scores and larger erythema areas compared to the normal control group （

P

＜0.05）， and histopathological examination revealed a significant infiltration of inflammatory cells， with some signs of deep connective tissue damage. Compared to the model group， the

Jiawei Jingqin Decoction

medium and high-dose groups showed a significant decrease in erythema scores and erythema areas （

P

＜0.05）， as well as a reduction in inflammatory exudates and inflammatory cell infiltration. However， the

Jiawei Jingqin Decoction

low-dose group did not show significant difference （

P

＞0.05）， but there was a slight reduction in inflammatory cell infiltration compared to the model group. When compared to the normal control group， the rosacea skin tissues of the model group showed an increase in the number of mast cells， levels of IL-1β， IL-6， TNF-α， mRNA expression of IL-1β， IL-6， TNF-α， TLR2， INF-γ， KLK5， MMP-9， protein expression of KLK5， MMP-9， and the number of CD4

+

T-positive cells （

P

＜0.05）. Compared to the model group， the

Jiawei Jingqin Decoction

medium and high-dose groups showed a decrease in the number of mast cells， levels of IL-1β， mRNA expression of IL-1β， TNF-α， and the number of CD4

+

T-positive cells. The

Jiawei Jingqin Decoction

high-dose group showed a decrease in IL-6， TNF-α levels， mRNA expression of IL-6， TLR2， INF-γ， MMP-9， protein expression of MMP-9， KLK5， and the number of CD4

+

T-positive cells， as well as a decrease in IFN-γ and STAT1 protein expression （

P

＜0.05） compared to the Model group.

Conclusion

2

Jiawei Jingqin Decoction

has significant improvement effect on the skin symptoms of roseacne in a mouse model. Its mechanism might be related to regulating skin immune inflammatory reactions， thereby reducing the release of pathogenic factors and inflammatory factors.