Influence of dexamethasone on airway inflammation and CD4+ CD25+ regulatory T cells of asthmatic rats

Objective To investigate dexamethasone on airway inflammation and CD4+ CD25 + regulatory T cells (CD4+ CD25 +Tr) of asthmatic rats,and elucidate the possible mechanism of dexamethasone in treatment of asthma.Methods 30 Wistar rats were randomly divided into control group,asthma group and dexamethasone-treated group.Bronchoalveolar lavage fluid (BALF) was collected,and cytology study was conducted.The lung tissue was obtained and pathologic analysis was done through HE stain.Flow eytometry was used to detect the CD4+ CD25 +Tr ratio in PBMCs.Results Total cells number,the percentage of lymphocytes,neutrophils and eosinophils (Eos)in BALF of dexamethasone-treated group were lower than that of asthma group (P＜0.05,P＜0.01).Compared with the asthma group,less infiltration of inflammatory cells in lung tissues was observed in the dexamethasone-treated group.CD4+ CD25 + Tr of asthma group was lower than that of control and dexamethasone-treated group (P＜0.05).Conclusion Dexamethasone could suppress airway inflammation of asthmatic rats,which probably be due to increasing the number of CD4+ CD25 + Tr. Key words: Dexamethasone/PD; Asthma; Inflammation; T-lymphocytes; CD4-positive T-lymphocytes