The Changs Of Regulatory CD4～+CD25～+T Lymphocytes In Rats With Chronic Obstructive Pulmonary Disease And The Effects Of Erythromycin

Objective To investigate the changes of regulatory CD4~+CD25~+ T lymphocytes in the rats with chronic obstructive pulmonary disease(COPD) and the therapeutic effects of erythromycin(EM). Methods 32 SD rats were divided into 4 groups randomly: the normal control, COPD group, low-dose erythromycin therapy and large-dose erythromycin therapy. COPD models were established by intratracheal instillation of lipoplysacchairde(LPS) twice and exposed to cigarette smoke daily. Total and differential cell counts in blood and bronchoaveolar lavage fluid(BALF) were calculated. At the same time, the numbers of CD4~+ and CD4~+CD25~+ cells in BALF and blood were determined by Flow cytometry, and pulmonary tissue pathomorphological changes were observed with microscopy. Results In BALF, the numbers of white cells from COPD group,low-dose erythromycin therapy group and large-dose erythromycin therapy group were higher than the normal control group(P<0.05), but the ratios of neutrophil were significantly decreased (P<0.001). The percentages of monocyte-macrophage in COPD model and low-dose erythromycin therapy group were higher than the normal control group and large-dose erythromycin group(P<0.001); and the ratio of lymphocyte in large-dose erythromycin was higher than others. The percentage of CD4~+CD25~+ cells of CD4~+ cells of blood in COPD model was significantly lower than the normal control (p<0.05), and improved to normal level after low-dose erythromycin therapy; moreover, in BALF, the ratio of CD4~+CD25~+/ CD4~+ in high-dose EM therapy group was significantly higher than others. Conclusion Rats with COPD had an decreased number of CD4~+CD25~+ cells. CD4~+CD25~+ cells might take part in the pathogenesis of COPD and EM 's therapeutic role was by increasing the number of CD4~+CD25~+ cells.