Study On Anti-mp Activity Of Platycodon Grandiflorum Effective Parts And Mechanism On Repairing AEC-?

Mycoplasma Pneumoniae(MP)is the smallest microorganism that can grow in the inanimate medium.MP pneumonia has been reported in more than 20%of pneumonia cases in children and the rate is increasing annually.Therefore,it is very important topic to find out the effective drugs to treat MPP from traditional Chinese medicine.QinbaiQingfei Concentrated pellets(Qinbai)is the first new drug of traditional Chinese medicine approved by Center for Drug Evaluation(CDE)that can be used to treat MPP in children.It has been found that the extract of platycodon grandiflorum was more active against MP in vitro than other drugs in Qinbai.The aim of this research is to definite the effective parts and components of anti-MP in vitro and vivo and explore the repairing mechanism to type ? alveolar epithelial cell(AEC-?),by inspecting the influence of the effective parts on pulmonary surfactant protein A(SP-A)and tissue growth factor beta(TGF-?)of rats infected by MP.Large of biological activity characteristics of platycodon grandiflorum have been reported.But no study focused on the effective parts and components against MP infection.The research of repairing mechanism of AEC-? in lung tissue that damaged by MP of traditional Chinese medicine has not been reported.Macroporous adsorbent resins has been used to eluteethanol extracts of platycodon grandiflorum with different concentrations of ethanol.The minimal inhibitory concentrations(MIC)of different elution component have been tested in vitro to determine the effective parts of platycodon grandiflorum against mycoplasma pneumoniae preliminarily.Detections of qualitative and quantitative and experiments of KILL-TIME curve and anti-MP in vivo have been done seperately on the effective part and observe the histopathological changes.Results:50%ethanol elution is the effective part of against MP.Saponins are the major constituent of the effective part.Total saponins in the effective parts is more than 70%.The content of platycodon grandiflorum saponin D is 68.14mg·g-1.MICs of total saponinsand platycodon grandiflorum saponin D of anti-MP in vitro are 32-64?g·mL-1 and 16-32?g·mL-1 respectively.Minimum bactericidal concentrations(MBC)are 64-128 ?g·mL-1and 32-64?g·mL-1 respectively.Growth and reproduction of MP in the cultivation has been inhibited completely in 7 days.Pathological examination showed that pathological changes mainly in the lungs and the degrees of inflammationare significantly reduced in all groups of platycodon grandiflorum effective parts and Platycodin D compared with model group.MPP model of rats was established by inoculated with MP through the nasal cavity.Drugs were administered by 7days.The lung tissue pathology change was observed by HE staining,and histopathological grading.The content of SP-A in serum and alveolar lavage fluid(BALF)was detected by enzyme-linked immunoassay(ELISA)method.Expression of mRNA of TGF-beta and SP-A in lung was tested by real-time quantitative PCR(RT-PCR)method.TGF-beta and SP-A protein expression of lung tissue was tested by Western blot method.To detectdetection of TGF-beta,SP-A distribution,localization and expression in lung tissue by Immunohistochemical method(IHC).by histopathologic grading,the improved rat lung tissue inflammation effect of platycodon grandiflorum effective parts and Platycodin on MPP show clear concentration-response relationship,and the effect of middle and high dose group have significant differences.Each dose group could reduce the content of SP-A in serum and increase the the content of SP-A in BALE,reduce TGF-beta mRNA and TGF-beta protein expression and increase SP-AmRNA and SP-A protein expression in the lung tissue.The TGF-beta was cytokines of cytoplasm expression,mainly distributed in pulmonary interstitial and alveolar walls.SP-A mainly distributed in the AEC-? and alveolar macrophages.Through the above research,determine the effective parts of platycodon grandiflorum resistance to MP were platycodon grandiflorum total saponins.Platycodin D was one of the active ingredient which have repair effect to Lung tissue damage caused by MP infection.and its mechanism may be accomplished through reducing the expression of TGF-beta.inhibit the AEC-? epithelial mesenchymal transformation(epithelial to mesenchymal transition,EMT),and increasing the content of SP-A in the lung tissue to restore the function of the AEC-?.The research for sieving the traditional Chinese medicine and clarifying mechanism of anti-MP provides the idea and method.Meanwhile the study is an important significance to enlarge the medication range and apply reasonably of platycodon grandiflorum.