Zi-Su-Zi Decoction Improves Airway Hyperresponsiveness in Cough-Variant Asthma Rat Model Through PI3K/AKT1/mTOR, JAK2/STAT3 and HIF-1α/NF-κB Signaling Pathways

Ethnopharmacological relevance: Cough-variant asthma (CVA) is one of the most common causes of chronic cough. Its pathogenesis is closely related to chronic airway inflammation and airway hyperresponsiveness. CVA belongs to the category of "wind cough" in Traditional Chinese medicine (TCM). Zi-Su-Zi decoction (ZSD) is a Chinese herbal formula that is clinically used for the treatment of cough and asthma, especially CVA. However, the mechanism of action remains unclear.Aim of the study: In this study, we aimed to explore the potential mechanism by which ZSD improves CVA airway hyperresponsiveness.Materials and methods: The targets of ZSD in CVA were studied using a Network pharmacology. The main chemical components of ZSD were detected and analyzed using ultra-high-pressure liquid chromatography (UHPLC-MS/MS). In animal experiments, the rat model of CVA was established using Ovalbumin (OVA)/ Aluminum hydroxide (AL(OH)3) sensitization. Moreover, the experiment also evaluated cough symptoms, percentage of eosinophils (EOS%), pulmonary function tests, histopathological sections, blood cytokine levels, mRNA and protein levels.Results: The results showed that Network pharmacology suggested 276 targets of ZSD and CVA and found that ZSD treatment with CVA was closely related to the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway. UHPLC-MS/MS revealed that ZSD contained 52 main chemical components. Compared with the model group, the cough symptoms of the rats in the different ZSD concentration groups were relieved, the EOS% index was lowered, and body weight was increased. HE staining showed that ZSD reduced airway inflammation, edema and hyperplasia, thereby improving the pathological structure of lung tissue, and the effect of high-dose ZSD was especially significant. Our most important finding was that ZSD blocked the entry of hypoxia-inducible factor-1a (HIF-1a), signal transducer and activator of transcription-3 (STAT3) and nuclear factor kappa-B (NF-?B) into the nucleus by interfering with PI3K/AKT1/mechanistic target of rapamycin (mTOR), and janus kinase 2 (JAK2) signaling factors. Consequently, inhibiting the release of cytokines and immunoglobulin-E, thereby reducing airway hyperresponsiveness (AHR) and partially reverses airway remodeling.Conclusions: This study showed that ZSD can improve airway hyperresponsiveness and partially reverse airway remodeling by inhibiting the PI3K/AKT1/mTOR, JAK2/STAT3 and HIF-1a/NF-?B signaling pathways. Therefore, ZSD is an effective prescription for the treatment of CVA.