| Objective:To observe the Intervention effects of Dendrobium Officinale Polysaccharide（DOP）on silicofibrosis mice,and to explore the mechanisms of DOP affecting Notch/Hes1signaling pathway in anti-silicofibrosis,which will provide a new candidate drug for clinical treatment of silicofibrosis.Methods:The mouse model of silicofibrosis was established by oropharyngeal instillation of silica（Silicon dioxide,SiO2）suspension.120 SPF grade Kunming mice were randomly divided into control group and model group.The mice in the control group were instilled with 200μL of normal saline,and the mice in the model group were instilled with 200μL of 50 mg·m L-1 SiO2 suspension to establish silicofibrosis model.HE and Masson staining were performed every other week to observe the formation time of silicofibrosis in mice.After successful modeling,the modeling groups were randomly divided into model group,positive drug（Pirfenidone,PFD）control group（PFD group）and DOP low,medium and high(125,250,500 mg·kg-1)dose groups,20 per group.The DOP low,medium and high dose groups and the PFD group were given the corresponding volume of drugs by gavage according to the weight of the mice,while the control group and the model group were given the same amount of normal saline.Then,samples were taken on 14 d and 28 d after administration:the general condition and body weight of the mice were observed;HE and Masson staining were used to observe the changes in the pathological structure of lung tissue;Changes in ultrastructure;calculation of hydroxyproline content and lung coefficient of mice in each group;determination of interleukin-6（Interleukin-6,IL-6）in lung tissue of mice by enzyme-linked immunosorbent assay（ELISA）,tumor necrosis factor-α（TNF-α）,laminin（LN）,hyaluronic acid（HA）,type III collagen（Collagen III,Col-III）and TypeⅣcollagen fibers（CollagenⅣ,Col-Ⅳ）;the relative expressions of Notch1,Hes1,Hey1,TGF-β1 and Col-ⅢmRNA in mouse lung tissue were detected by real-time PCR（qRT-PCR）;The protein expressions of Notch1,Hes1,Col-Ⅲand TGF-β1 in lung tissue were detected by immunohistochemistry method;the relative expressions of Notch1,Hes1,Jagged1 andα-SMA proteins in lung tissue were detected by Western Blot method.Results:（1）The mice in the control group and the four administration groups had good diets and mental state,and were more active;the mice in the model group had reduced diets,poor mental state,significantly reduced activity,and some even showed symptoms of hypoxia.Compared with the control group,the body weight of the mice in the model group after administration for 28 days decreased with statistical significance（P<0.05）.（2）The degree of alveolar inflammation and silicofibrosis in the lung tissue of mice in the model group after administration for 14 days and 28 days.significantly worse than the control group.Compared with the model group,the alveolar inflammation and silicofibrosis in the four drug-administered groups were improved to varying degrees by drug treatment;the lung tissue of the control group was smoother than the other five groups.,there were no obvious gray nodules.（3）The ultrastructure of lung tissue in the six groups was observed by transmission electron microscope after 28 days of administration,and it was found that the lung tissue of the model group and the four administration groups could clearly see the formation of collagen fibers,and Compared with the four administration groups,the ultrastructure of the model group was seriously damaged.（4）The HYP content and lung coefficient of the lung tissue of the mice in the model group were significantly increased compared with the control group for 28 days,and the difference was statistically significant.（P<0.01）;the HYP content in the lung tissue of the four administration groups was significantly decreased,indicating that PFD and DOP can reduce the production of HYP and collagen fibrin,so PFD and DOP can delay the process of silicofibrosis.（5）The contents of IL-6,TNF-α,LN,HA,Col-III and Col-IV in the lung tissue of mice in the model group were higher than those in the control group for 28 days,and the difference was statistically significant（P<0.01）.Compared with the model group,the four administration groups have different degrees of reduction,and the effects of the DOP medium and high dose groups were the most obvious.（6）The relative expression levels of Notch1,Hes1,Hey1,TGF-β1 and Col-III mRNA in the model group after administration for 14 days and for 28 days were higher than those in the control group,and the difference was statistically significant（P<0.01）.（7）Compared with the control group,the relative expressions of Notch1,Hes1,TGF-β1 and Col-Ⅲproteins in the model group were significantly increased,and the difference was statistically significant（P<0.01）.The proteins of Notch1,Hes1 and Col-Ⅲwere decreased in the DOP group and DOP medium and high dose groups,and the difference was statistically significant（P<0.05 or P<0.01）.Although there was a downward trend in the expression level,the difference was not statistically significant.（8）The relative protein expressions of Notch1,Hes1,Jagged1 andα-SMA in the model group after administration for 28 days were significantly higher than those in the control group,and the difference was statistically significant（P<0.01）;PFD group and DOP low and medium doses The relative protein expressions of Notch1,Hes1,Jagged1 andα-SMA in the DOP group were significantly decreased,and the difference was statistically significant（P<0.05 or P<0.01）.Although there was a downward trend in the expression level,the difference was not statistically significant.Conclusion:（1）DOP can reduce the contents of intracellular inflammatory factors,reduce inflammatory cell infiltration,delay the progression of silicofibrosis,and improve the degree of silicofibrosis.（2）DOP can effectively improve the degree of silicofibrosis by inhibiting the Notch/Hes1 signaling pathway,thereby reducing the synthesis and release of collagen fibrin. |
