Expression and significance of Th17 cell and IL-21 in rat pulmonary fibrosis model

Objective To investigate the expression and significance of Th17、interleukin-21in the pathogenesis of pulmonary fibrosis.Methods 64SD rats were randomly divided into three groups:pulmonary fibrosis model group(P,n=24),dexamethasone 3mg/kg intervention(D,n=16),normal saline control group(N,n=24).GroupP,D injected Bleomycin(5mg/kg)intratracheal to establish rat model of pulmonary fibrosis,Group N intratracheal instillated equal amount of 0.9%sodium chloride injection.Group D injected dexamethasone intraperitoneal everyday after the 6th days;Group N,P injected the same amount of 0.9%sodium chloride injection.At 7th,14th,28th days after modeling randomly sacrificed rats(8/group)to observe the pathological changes and determinate HYP of lung tissue;Determinate Th17cells accounted of proportion of CD4+T cells by flow cytometry.Detect the expression level of IL-21by fluorescent RT-PCR method.Results After Bleomycin injection,rat lung tissue early inflammatory reaction,and the gradual emergence of fibrosis and collagen fibers.in the P group,the expression levels of IL-21and Th17cells accounted the the proportion the CD4+T cells significantly higher than those in N group(P0.05),the highest expression levels at 7th day,then decreased gradually.Conclusion Th17cells and IL-21factor plays an important role in the pathogenesis of pulmonary fibrosis in rats,may be involved in the occurrence and development of pulmonary fibrosis.