Xiaoqinglong decoction mitigates nasal inflammation and modulates gut microbiota in allergic rhinitis mice.

Introduction: Allergic rhinitis (AR) is a respiratory immune system disorder characterized by dysregulation of immune responses. Within the context of AR, gut microbiota and its metabolites have been identified as contributors to immune modulation. These microorganisms intricately connect the respiratory and gut immune systems, forming what is commonly referred to as the gut-lung axis. Xiaoqinglong Decoction (XQLD), a traditional Chinese herbal remedy, is widely utilized in traditional Chinese medicine for the clinical treatment of AR. In this study, it is hypothesized that the restoration of symbiotic microbiota balance within the gut-lung axis plays a pivotal role in supporting the superior long-term efficacy of XQLD in AR therapy. Therefore, the primary objective of this research is to investigate the impact of XQLD on the composition and functionality of the gut microbiota in a murine model of AR. Methods: An ovalbumin-sensitized mouse model to simulate AR was utilized, the improvement of AR symptoms after medication was investigated, and high-throughput sequencing was employed to analyze the gut microbiota composition. Results: XQLD exhibited substantial therapeutic effects in AR mice, notably characterized by a significant reduction in allergic inflammatory responses, considerable alleviation of nasal symptoms, and the restoration of normal nasal function. Additionally, following XQLD treatment, the disrupted gut microbiota in AR mice displayed a tendency toward restoration, showing significant differences compared to the Western medicine (loratadine) group. Discussion: This results revealed that XQLD may enhance AR allergic inflammatory responses through the regulation of intestinal microbiota dysbiosis in mice, thus influencing the dynamics of the gut-lung axis. The proposal of this mechanism provides a foundation for future research in this area.

HDAC Downregulation of Xiaoqinglong Decoction in the Treatment of Allergic Rhinitis.

INTRODUCTION: As one of the most common allergic diseases, allergic rhinitis (AR) has attracted wide attention all over the world. More appropriate treatment of AR should be explored thoroughly. In recent years, traditional Chinese medicine has attracted more attention in AR treatment. As a classical Chinese medicine prescription, Xiaoqinglong decoction (XQLD) has been commonly used in treating AR. Even though its therapeutic effect on AR has been clinically confirmed, more molecular mechanism remains to be further investigated. Our research aimed to investigate the therapeutic mechanism of XQLD for AR management. METHODS: The study was evaluated in an ovalbumin sensitized mouse model and liquid chromatography-mass spectrometry was adopted to test the stability of XQLD's effective components. RESULTS: The results confirmed the stability and safety of the effective components of XQLD. XQLD significantly downregulated the expression of HDACs (HDAC1, HDAC3, and HDAC4) and Th2 inflammatory factors (IL4, IL5, and IL13) in AR mice. XQLD and the HDAC inhibitor JNJ-26481585 promoted the expression of epithelial tight junction proteins (claudin-1 and ZO-1) and decreased the expression of mucins (Muc5ac and Muc5b) in the nasal mucosa of AR mice. CONCLUSIONS: In conclusion, our findings present the beneficial effects of XQLD on AR and recovery of the nasal epithelium. We also identify the decreased HDAC as a potential target of XQLD for AR treatment. This study provides an important experimental proof for elucidating the therapeutic mechanism of XQLD.

Efficacy and safety of the Chinese herbal medicine Xiao-qing-long-tang for allergic rhinitis: A systematic review and meta-analysis of randomized controlled trials.

ETHNOPHARMACOLOGICAL RELEVANCE: The classic Chinese herbal medicine formula Xiao-qing-long-tang (XQLT) is commonly recommended to manage allergic rhinitis (AR), but the treatment efficacy and safety of XQLT are uncertain. AIM OF THE STUDY: This study aimed to evaluate the effectiveness and safety of XQLT in treating AR. MATERIALS AND METHODS: Nine databases were searched from their inception to April 2021. Randomized controlled trials (RCTs) evaluating XQLT for AR were included. The methodological quality of the studies was assessed using the Cochrane risk-of-bias tool. A meta-analysis and a subgroup meta-analysis were conducted to evaluate the effectiveness of XQLT. RESULTS: Twenty-four RCTs were included in this meta-analysis. XQLT was compared to both placebo and Western medicine (WM), and XQLT combined with WM was compared with WM alone. Meta-analyses were conducted for total nasal symptom scores (TNSS), four individual nasal symptom scores, quality of life (QoL), effective rate, and recurrence rate. The TNSS decreased after XQLT treatment and combination treatment (mean difference (MD): -0.79; 95% confidence interval (CI) [-1.20, -0.38], standardized mean difference (SMD): -1.42; 95% CI [-1.59, -1.24], and SMD: -1.84; 95% CI [-2.08, -1.60]). The two individual nasal symptom scores decreased after XQLT treatment and combination treatment; these nasal symptoms comprised rhinorrhea (SMD: -0.30; 95% CI [-0.58, -0.02] and SMD: -0.48; 95% CI [-0.70, -0.26]), and nasal obstruction (SMD: -0.54; 95% CI [-0.78, -0.30] and SMD: -0.54; 95% CI [-0.76, -0.32). XQLT and XQLT combined with WM achieved a better effective rate than WM (risk ratio (RR): 1.18; 95% CI [1.11, 1.25] and RR: 1.16; 95% CI [1.10, 1.23]) and a lower recurrence rate than WM (RR: 0.24; 95% CI [0.13, 0.43] and RR: 0.47; 95% CI [0.31, 0.72]). XQLT was well tolerated in patients being treated for AR. CONCLUSION: Our results indicated that oral XQLT may alleviate the TNSS, rhinorrhea scores, and nasal obstruction scores of AR and is safe to use in clinical practice. However, more RCTs that follow rigorous methodologies and evaluate well-accepted outcome measures are required to evaluate the effectiveness of XQLT.