RESUMEN
Cough variant asthma （CVA） is a chronic respiratory disease with cough as its main symptom. The occurrence of CVA is closely related to non-specific airway inflammation， and its pathogenesis involves environmental， genetic， immune， and other factors. In recent years， the advantages of traditional Chinese medicine （TCM） in the treatment of CVA have attracted the attention of experts and scholars in China and abroad， especially its prominent role in regulating immune balance， relieving cough symptoms in CVA patients， and reducing recurrence. T Helper cells 1 （Th1）， T helper cells 2 （Th2）， T helper cells 17 （Th17）， and regulatory T cells （Treg） are derived from CD4+ T cells. Immune imbalance of Th1/Th2 and Th17/Treg is a new hotspot in the pathogenesis of CVA and a potential key target in the treatment of CVA by TCM. Th cell subsets are in dynamic balance under physiological conditions， maintaining respiratory immune homeostasis in which pro-inflammatory cytokines and anti-inflammatory cytokines are balanced. Immature helper T cells （Th0） can be differentiated into Th1， Th2， Th17， Treg， and other cell subsets due to cytokine types in the microenvironment in the stage of CVA maturation. The proliferation of Th2 cells leads to eosinophilic airway inflammation. Excessive differentiation of Th17 cells induces neutrophil airway inflammation. Th1/Th2 and Th17/Treg cells are mutually restricted in number and function， and the immune imbalance of Th1/Th2 and Th17/Treg is easy to aggravate the generation of inflammatory response. Restoring immune balance is particularly important for the airway anti-inflammatory therapy of CVA. In this paper， the imbalance of Th1/Th2 and Th17/Treg and the pathogenesis of CVA were systematically expounded. Meanwhile， the latest research on the regulation of immune imbalance by TCM compound， single TCM， and its effective ingredients in the treatment of CVA was reviewed. It provides ideas and references for revealing the scientific connotation of TCM regulating immune balance therapy of CVA， as well as the development of clinical treatment and basic research of CVA.
RESUMEN
ObjectiveTo investigate the effect of icariin （ICA）-mediated vitamin D system on peripheral blood dendritic cells （DCs） and helper T cells 17 （Th17）/regulatory T cells （Treg） balance in myocardial remodeling model of Dahl salt-sensitive rats. MethodFifty SPF Dahl salt-sensitive rats were divided into model group， vitamin D group （3×10-5 mg·kg-1·d-1）， and high-， medium-， and low-dose ICA groups （120， 60， 30 mg·kg-1·d-1）， and 10 Dahl salt-resistant rats were used as normal group. The myocardial remodeling model was established by feeding rats with a high-salt diet containing 8% NaCl. After six weeks of modeling， the normal group and the model group were given an equal volume of ultrapure water by gavage， and other groups were continuously administrated for six weeks. Cardiac echocardiography， hematoxylin-eosin （HE） staining， and Masson staining were used to observe the pathological changes in cardiac structure and fibrosis. The levels of serum 25（OH）D3， B-type N-terminal pro-brain natriuretic peptide （NT-ProBNP）， interleukin （IL）-17， transforming growth factor （TGF）-β1， IL-12， and IL-10 were detected by enzyme-linked immunosorbent assay （ELISA）. The phenotype of peripheral blood DCs and the ratio of Th17/Treg cells of rats were detected by flow cytometry. Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） and Western blot were used to detect the mRNA and protein expressions of vitamin D receptor （VDR），1α-hydroxylase （CYP27B1）， and 24-hydroxylase （CYP24A1） in peripheral blood DCs of rats. ResultCompared with the control group， the rats in the model group had pathological changes such as disordered arrangement of myocardial cells and cytoplasmic hypertrophy and swelling. Myocardial collagen fibers proliferated significantly， and the arrangement of myocardial fibers was disordered. The levels of serum 25（OH）D3 and IL-10 were significantly decreased， and the levels of serum IL-17， TGF-β1， IL-6， IL-12， and NT-ProBNP were significantly increased （P<0.05）. The costimulatory molecules CD40， CD80， CD86， and MHC-Ⅱ were highly expressed in the peripheral blood DCs， and the expression of CD11 and CD11b was lower （P<0.05）. The proportion of Th17 cells in the peripheral blood was significantly increased， and the proportion of Treg cells was decreased. The ratio of Th17/Treg was increased （P<0.05）. The mRNA and protein expressions of CYP24A1 in peripheral blood DCs increased， and the mRNA and protein expressions of CYP27B1 and VDR decreased （P<0.05）. Compared with the model group， the arrangement of myocardial fibers in each drug administration group was relatively regular， and the swelling of myocardial cells was significantly reduced. The pathological morphology of myocardial tissue was improved to varying degrees. The pathological changes in myocardial tissue were improved and alleviated to varying degrees. The drug could reduce the serum levels of NT-ProBNP， IL-17， TGF-β1， IL-6， and IL-12 and increase the level of serum 25（OH）D3 and IL-10 （P<0.05）. The expression of costimulatory molecules CD40， CD80， CD86， and MHC-Ⅱ in the peripheral blood DCs of rats was decreased， and the expression of CD11 and CD11b molecules was increased （P<0.05）. The drug could reduce the proportion of Th17 cells in peripheral blood and the ratio of Th17/Treg cells and increase the proportion of Treg cells （P<0.05）. It could decrease the mRNA and protein expressions of CYP24A1 in peripheral blood DCs of rats and elevate the mRNA and protein expression of VDR and CYP27B1 （P<0.05）. ConclusionICA can regulate the phenotype of peripheral blood DCs and the ratio of Th17/Treg cells by regulating the vitamin D system and play a role in improving myocardial remodeling from the perspective of immune balance.