Interventional Effect And Mechanism Of Schisandrin B On Bleomycin-induced Pulmonary Fibrosis In Mice

Idiopathic Pulmonary Fibrosis(IPF)is a chronic,inflammatory,interstitial lung disease,often occurring in middle-aged and elderly people,and characterized by progressive,irreversible,and fatal features.The incidence of IPF worldwide is increasing year by year,and the 5-year survival rate of patients is less than 30%.The specific clinical manifestations of IPF are exertion dyspnea,which is progressively aggravated with the development of the disease,accompanied by tachypnea and nasal alar agitation.In severe cases,there may be mouth cyanosis,thoracic dilatation,and decreased diaphragm activity,etc.,requiring oxygen making machine to assist breathing.Coughing and sputum,early clinical manifestations are mainly dry cough or cough mucus sputum,if there is pulmonary infection can be seen bloody sputum or purulent sputum;The quality of life of patients in the late stage of the disease is severely reduced,and the common cause of death is respiratory failure.Current studies have found that anti-fibrosis drugs such as pirfenidone and nidanibu can improve the symptoms of IPF patients and delay the decline of lung function,but can not significantly improve the survival rate of patients and improve the quality of life in the later stage of patients,and the safety has not been fully proved.In addition,glucocorticoids,immunosuppressants and cytotoxic drugs are also used in the treatment of pulmonary fibrosis,but long-term use has significant side effects.In recent years,the research interest of IPF in Chinese medicine has been increasing gradually,and corresponding achievements have been made,which can be used to guide clinical practice.In addition,TCM compounds and monomers also play a unique role in the treatment of IPF.Therefore,it is necessary to explore the mechanism of Chinese herbal medicine and related preparations in the treatment of idiopathic pulmonary interstitial fibrosis.Research purposeIn this study,bleomycin-induced pulmonary fibrosis mice were used as a model.By analyzing the levels of relevant fibrosis,oxidation and antioxidant indicators,the intervention effect and mechanism of Schisandrin B on pulmonary fibrosis were explored.Research methodsTwenty-four healthy male C57BL6 mice were randomly divided into blank group,model group and SCH-B group,with 8 mice in each group.After adaptive feeding for 1 week,the blank group was given 0.9%sodium chloride injection(NS)in the trachea under anesthesia,and the other two groups were given bleomycin via the trachea to establish pulmonary fibrosis model.On the second day after modeling,0.9%NS was given daily to the blank group and model group,and Schisandrae ethanetin was given daily to the Sch-B group.All groups were killed by dislocation on the 14th day,and the pathological changes of lung tissue were observed by HE staining and Masson staining.The content of 8-iso-PGF and hydroxyproline(HYP)were determined by enzyme-linked immunosorbent assay(ELISA)kit,and the degree of oxidative damage and fibrosis in lung tissue of mice in each group was observed.The contents of superoxide dismutase(SOD)and heme oxygenase(HO--1)were detected by PCR,and the degree of antioxidant damage in lung tissue of mice in each group was observed.The therapeutic effect was evaluated by the above detection methods.Research resultsThe results of HE staining showed that compared with the model group,the degree of alveolar damage and septal thickening was relatively mild,the infiltration of inflammatory cells was relatively less,the degree of pulmonary interstitial fibrosis was relatively mild,the degree of alveolar structural damage and inflammation were significantly reduced,and the inflammatory score of lung tissue was significantly lower in SCH-B group than in the model group(P<0.01).Masson staining results showed that compared with the model group,the damage degree of alveolar structure in the lung tissue of mice in SCH-B group was relatively mild,the area of lung interstitium,bronchial wall and alveolar septum was relatively small,and the formation and deposition area of collagen fibers were significantly lower than that in the model group(P<0.01).The results of fluorescence quantitative PCR showed that SOD and HO-1 levels in sch-B group were significantly higher than those in the model group(P<0.01).The results of enzyme-linked immunosorbent assay(ELISA)showed that the HYP and 8-ISo-PGF levels of mice in the SCH-B group were significantly lower than those in the model group(P<0.01).Research conclusionSchisandrin B may reduce the degree of pulmonary fibrosis by increasing the level of tissue antioxidant,reducing inflammatory reaction and oxidative damage,inhibiting the process of pulmonary fibrosis.