Therapeutic effects of the Qingre-Qushi recipe on atopic dermatitis through the regulation of gut microbiota and skin inflammation

Abstract

Accumulating evidence has highlighted a strong association between gut microbiota and the occurrence, development, prevention, and treatment of atopic dermatitis (AD). The regulation of gut microbial dysbiosis by oral traditional Chinese medicine (TCM) has garnered significant attention. In the treatment of AD, the TCM formula Qingre-Qushi Recipe (QRQS) has demonstrated clinical efficacy. However, both the therapeutic mechanisms of QRQS and its impact on gut microbiota remain unclear. Thus, our study aimed to assess the efficacy of QRQS and evaluate its influence on the composition and diversity of gut microbiota in AD animal models. First, we investigated the therapeutic effect of QRQS on AD using two animal models: filaggrin-deficient mice (Flaky tail, ft/ft) and MC903-induced AD-like mice. Subsequently, we explored its influence on the composition and diversity of gut microbiota. Our results demonstrated that QRQS treatment ameliorated the symptoms in both ft/ft mice and MC903-induced AD-like mice. It also reduced the levels of serum IgE and pro-inflammatory cytokines, including IL-1β, IL-4, IL-5, IL-9, IL-13, IL-17A, and TNF-α. Furthermore, QRQS remarkably regulated gut microbiota diversity by increasing Lactobacillaceae and decreasing Bacteroidales. The inflammatory factors in peripheral serum of ft/ft mice showed a close correlation with gut microbiota, as determined using the Spearman correlation coefficient. Additionally, PICRUSt analysis revealed an enrichment in ascorbate and aldarate metabolism, fatty acid metabolism and biosynthesis, and propanoate metabolism in the QRQS group compared to the ft/ft group. Finally, we identified liquiritin as the primary active ingredient of QRQS using ultra-high-performance liquid chromatography-high-resolution mass spectrometry (UPLC-HRMS). Our findings revealed that QRQS improved AD-like symptoms and alleviated skin inflammation in ft/ft and MC903-induced mice. This suggests that modulating the gut microbiota may help elucidate its anti-inflammation activation mechanism, highlighting a new therapeutic strategy that targets the intestinal flora to prevent and treat AD.

Keywords: Atopic dermatitis; Gut microbiota; QRQS; Skin inflammation; Traditional Chinese Medicine.

Fig. 1

QRQS attenuates AD-like symptoms in ft/ft mice. a Experimental design of ft/ft mice. Ft/ft mice developed a severe AD-like clinical phenotype at week 32. Oral administration of treatments was given daily from week 32 for 14 consecutive days. b Representative images of skin lesion and hematoxylin and eosin (H&E) staining in different groups, scale bar = 250 μM. c EASI scores, d scratching frequency, e epidermis thickness and f serum IgE level of each group. Means ± SD, n = 6–8. *p < 0.05, **p < 0.01, and ***p < 0.001 vs. ft/ft group, ^##p < 0.01 vs. Pred group, one-way ANOVA with Tukey's post-test. Pred: prednisone acetate, AB: antibiotics (ceftriaxone sodium), PB: probiotics (Bifico).

Fig. 2

QRQS inhibits the level of inflammatory factors. Comparison of inflammatory factors in serum of different groups. Means ± SD, n = 8. *p < 0.05, **p < 0.01, and ***p < 0.001, one-way ANOVA with Tukey's post-test.

Fig. 3

Effect of QRQS on the diversity and composition of gut microbiota in ft/ft mice. a α-diversity analysis including Shannon, Simpson, Chao and Ace indexs on OTU level. b PLS-DA score plot on OTU level. c The heatmap of microbiota of each groups based on family level. f Taxonomic cladogram based on the on the linear discriminant analysis effect size (LEfSe) analysis. e Linear discriminant analysis (LDA) score of ft/ft group vs. QRQS group. n = 6–8, *p < 0.05, and ***p < 0.001 vs. ft/ft group, ^###p < 0.001 vs. AB group, Kruskal-Wallis H test. AB: antibiotics (ceftriaxone sodium), PB: probiotics (Bifico).

Fig. 4

Heatmap of Spearman's rank correlations of gut microbiota between serum level of inflammatory cytokines. Positively correlated samples are shown in red color and negative in blue. *p < 0.05, **p < 0.01, and ***p < 0.001. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)

Fig. 5

Functional analysis of the gut microbiota using PICRUSt. a Differential pathways presented in QRQS and ft/ft groups with PICRUSt analysis. b Sankey diagram of 3 level classifications of differential metabolism pathway. c Top 12 differential pathways identified in the ft/ft group vs. QRQS group. Bar plots on the left side displayed the proportion of each KEGG pathway. Dot plots on the right show the differences in mean proportions between the two indicated groups using p-values, *p < 0.05, **p < 0.01, and ***p < 0.001.

Fig. 6

Quality control analysis of the QRQS formula. a UPLC-HRMS chromatograms of QRQS in positive and negative modes. b HPLC chromatogram of QRQS extract and liquiritin as standard compounds.

figs1

Supplementary Fig. S1. QRQS attenuates AD-like symptoms in MC903-induced mice. a Experimental design of MC903-induced AD mice. C57BL/6 mice were topically administered of 5 nmol MC903 on dorsal skin daily for 2 × 6 days with a 2-day interval. Oral administration of treatments was given daily for 14 consecutive days. b Representative images of skin lesion and H&E staining in different groups, scale bar = 250μM. c EASI scores, d weight, e scratching frequency, f epidermis thickness, and serum IgE of each group. Means ± SD, n=5. *p<0.05, and ***p<0.001, one-way ANOVA with Tukey's post-test. Ceti: Cetirizine.

figs2

Supplementary Fig. S2. The differences of predicted biological function between QRQS and PB. Bar plots depict the mean proportion and differences in mean proportions with 95% confidence intervals in the QRQS. group vs. PB group, Student t test (two-sided). PB: probiotics (Bifico).

figs3

Supplementary Fig. S4. HPLC chromatogram of oxymatrine and sophocarpin.