Objective:To investigate the changes of thymic lymphocyte procyanidin(TSLP)and interleukin-4(IL-4),interleukin-10(IL-10)and interleukin-13(IL-13)in the lung tissue of young rats infected with respiratory syncytial virus,and to investigate the changes of TSLP and Th2 Correlation.Methods:18 Wistar rats were randomly divided into RSV infection group and normal group,9 rats in each group.Application of RSV virus droplets nasal modeling,saline diarrhea as a control.The lung tissue of rats was taken for pathological observation;the load of syncytial virus at different time points and the expression of TSLP in lung tissue were detected by Real-time quantitative polymerase chain reaction(q-PCR);at the same time,the expression of TSLP at the protein level was detected by Western blot.The levels of cytokines IL-4,IL-10 and IL-13 in serum were measured by enzyme-linked immunosorbent assay(ELISA).And the relationship between TSLP and IL-4,IL-10 and IL-13 was analyzed by Spearman correlation.Results:Compared with the normal control group,the rats in the model group showed symptoms such as poor mental state,rough hair,decreased activity and shortness of breath after intranasal infection,and the symptoms were aggravated.Pathological observation showed that the alveolar wall was thickened in the model group,and a large number of lymphocytes,plasma cells,eosinophil infiltration.q-PCR was used to detect the syncytial virus load in model group,and reached the peak at about 5 days,then decreased gradually.RSV infection increased the secretion of TSLP in rat respiratory tract.q-PCR and Western blot showed that TSLP concentration in model group was higher than that in control group(P<0.05).The levels of IL-4,IL-10 and IL-13 in the serum of the model group were higher than those in the control group(P<0.05).Spearman correlation analysis showed that TSLP was positively correlated with IL-4 and IL-10 expression in RSV model group,and there was no correlation between TSLP and IL-13 expression.Conclusion:RSV infection in rat lung tissue can induce increased expression of TSLP,while promoting the occurrence of Th2 type of inflammatory response and the expression of related cytokines,in order to further study of RSV infection caused by bronchiolitis and asthma and other respiratory diseases,the mechanism of action and clinical treatment laid the foundation.