Influences Of Dexamethasone And Erythromycin On CD4～+CD25～+ Regulatory T Cells In Rats With Chronic Obstructive Pulmonary Disease

Objective (1)To draw a comparison between therapic effects ofdexamethasone(DEX) and erythromycin(EM) in chronic obstructive pulmonarydisease(COPD), and To compare with influences of both on CD4+CD25+regulatory T cells.Methods rats were randomly divided into four groups: normal controlgroup, COPD group (model group), EM treatment groups, and DEX treatmentgroups. The rat models of COPD were established by intratracheal instillation oflipopolysaccharide (LPS) twice and exposure to cigarette smoke daily. DEXtreatment groups and EM treatment groups received intraperitoneal injectionand gastric gavage respectively , starting on the 14th day. At the end of fourthweeks, total and differential cell counts in blood and bronchoaveolar lavagefluid(BALF) were observed, percentage of CD4+CD25+T cells about CD4+ Tcells from BALF and blood were measured by Flow cytometry, and thepathomorphological sections of lung tissues were received and analyzed.Results (1) The COPD group rats shared specific pathological features intrachea, bronchi and lung tissues with that of chronic bronchitis and emphysema.Average pulmonary alveoli area ,BALF inflammatory cell number andpercentage of neutrophils were higher than those in control group(P < 0.05).CD4+CD25+ T cells from blood (percentage of CD4+CD25+ T cells comparedwith CD4+ T cells) was decreased significantly than that in control group (P <0.05). (2) CD4+CD25+ T cells from blood and BALF in DEX treatment groupswere significantly increased than those in COPD group(P < 0.01), but BALFinflammatory cell number was significantly decreased(P < 0.05), under themicroscope, the infiltration of inflammatory cells in airway inflammation ofDEX treatment groups were improved. (3) CD4+CD25+ T cells from blood inEM treatment groups was also increased than that in control group (P < 0.01),although CD4+CD25+ T cells from blood was increased, Compared with theCOPD group, it was not statistical significance(P > 0.05), at one time, BALFinflammatory cell number and percentage of neutrophils were markedlydecreased (P < 0.05).Conclusion The mechanism of DEX and EM improving inflammatorycells of COPD is possibly by increasing CD4+CD25+ T cells from blood and/orBALF.