Objective To study the expressions of thymic stromal lymphopoietin (TSLP),GATA-3 transcription factor and serum interleukin (IL)-4 and IL-13 in lung tissue of young rats infected with respiratory syncytial virus (RSV) at different time points,and to analyze the expression level of TSLP and its downstream related factors.Methods Sixty healthy Wistar rats were randomly divided into normal group and model group.Under the ether anesthesia,RSV Long virus solution was inoculated into the nasal cavity of the model group for 3 days,once a day,and the virus infection model was established.The normal conditions of the 2 groups were observed and recorded on the 3rd,5th and 7th day after the model was established.The expression levels of RSV mRNA,TSLP and its downstream factors were analyzed by real-time polymerase chain reaction and enzyme-linked immunosorbent assay.Results (1)Compared with the normal group,the model group was in poor condition and progressively increased.(2) After the RSV infection,the virus load in the model group reached the peak on the 5th day,which was 4.58 ±0.21.(3)The expression levels of TSLP at the corresponding time points were 0.94 ± 0.26,1.27 ± 0.10 and 1.27 ± 0.01,respectively,which were significantly higher than those in the normal group on the 5th,7th day (t =-11.409,-57.482,all P ＜0.05).(4) The expression of GATA3 at the each time point in the model group were 1.16 ± 0.07,2.61 ± 0.41 and 0.64 ± 0.06,raspectively,which were higher than those in the normal group,and the expression level of GATA3 was statistically significant (t =-26.899,-10.637,-15.187,all P ＜ 0.05).(5) Compared with the normal group,the expressions of IL-4 and IL-13 in the model group were higher than those in the normal group,and the expressions level of IL-4 and IL-13 in the model group showed an increasing trend.Conclusion RSV infected rats can up-regulate the dynamic response of Th2 cells by increasing the expression of TSLP,GATA3 transcription factor and IL-4 and IL-13.