Xiaoqinglong Decoction Attenuates Inflammatory Response and Mitochondrial Injury by Regulating the MyD88/NF-κB Pathway Dependent of TLR4 in Allergic Rhinitis

Introduction: Allergic rhinitis (AR) is a systemic immune inflammatory response disease of the nasal mucosa. Current treatment strategies for AR are limited, owing to a lack of safety and the inability to cure the condition completely. Xiaoqinglong decoction (XQLD), a classical chinese medicine prescription, is widely used to treat AR with a good curative effect. Although the clinical effect of XQLD has been demonstrated, the molecular mechanisms of therapeutical effect were unclear. Hence, the study aimed to investigate effects of XQLD on inflammation and the underlying mechanism for AR management. Methods: Ovalbumin sensitization was used to induce AR in rats, and the nasal symptoms were evaluated. Hematoxylin-eosin staining was performed to detect epithelial cells of the nasal mucosa. Inflammatory factors were estimated to evaluate the anti-inflammatory effect of XQLD. Toll-like receptor 4 (TLR4) activity and myeloid differentiation factor 88 (MyD88)/nuclear factor kappa B (NF-κB) pathway were determined via immunofluorescence and Western blotting. Mitochondrial morphology and damage-related factors were assessed to determine the protective effect of XQLD. Results: The results showed that XQLD supplementation inhibited AR-induced release of inflammatory factors, relieved nasal symptoms, and improved mitochondrial functions. Moreover, it suppressed TLR4 and MyD88 expression as well as NF-κB p65 acetylation following AR. Conclusion: Inflammatory response and mitochondrial injury and the related MyD88/NF-κB signaling pathway play crucial roles in AR. XQLD supplementation inhibits AR-induced inflammation and mitochondrial injury by regulating TLR4 expression and TLR4-mediated MyD88/NF-κB pathway activation, thereby facilitating the therapeutic effect.