Effects of Radix Platycodonis Polysaccharide on Expressions of IFN-γ, IL-4 and IL-5 in the Bronchoalveolar Lavage Fluid and NF-kB in the Lung Tissue of Asthmatic Rats

摘要

To investigate the effect of Radix playtycodoni polysaccharide (RPPS) on rats with ovalbumin-induced asthma and its mechanisms. Methods: 48 Wistar rats were randomly divided into blank control group, asthma model group, dexamethasone control group (1 mg/kg), and high-dose RPPS group (40 mg/kg), moderate-dose RPPS group (20 mg/kg) and low-dose RPPS group (10 mg/kg). The ovalbumin sensitization method was used to establish the asthma model in rats. The rats were given it in the atomization administration for two weeks and then were sacrificed. The BALF was collected for the count of eosinophils (EOS); enzyme-linked immunosorbent assay (ELISA) method was employed for the determination of IL-4, IL-5, and IFN-γ levels in BALF; the expression of NF-κВ in the lung tissues was measured by Western blot. Results: Compared with the model group, RPPS could reduce the number of EOS in blood and BALF, increase the content of IFN-γ in BALF, lower IL-4 and IL-5 contents, and down-regulate the expression of NF-KB protein in rats with asthma. Conclusion: RPPS can inhibit the airway inflammation in asthma, down-regulate the expression level of IL-4 and IL-5, up-regulate the IFN-γ level to regulate the abnormal immune status induced by the imbalance of TH1/TH2 in asthma and inhibit the expression of NF-kB, which may be one of the mechanisms of its anti-inflammatory activity. Bronchial asthma is a common respiratory allergic disease with a high incidence. The typical pathology change of bronchial asthma is a chronic airway inflammation, in which a variety of inflammatory cells such as eosinophils, lymphocytes and neutrophils, and related cytokines are involved. In the modern therapy, glucocorticoids and several other drugs are primarily used to exert their anti-inflammatory effects, but the long-term application of them can induce some significant side effects. Radix playtycodonis (Platycodon grandiflorum) is a traditional Chinese medicine growing in China, which can ventilate the lung and dispel wind pathogens, and is commonly used for the treatment of cough with lung heat, exopathic wind cold or wind-heat-induced cough, and sore throat. Radix playtycodonis polysaccharide (RPPS), one of main components in Radix playtycodonis, has a variety of biological activities. In this study, based on the traditional Chinese medicine theory and, an attempt was made to explore the anti-asthmatic mechanism of RPPS by using modern biological techniques to provide a theoretical basis for the development of new drugs used in the treatment of asthma.