Effect of cold-dryness on pulmonary and immunologic function in chronic obstructive pulmonary disease model rats

OBJECTIVE： To study the effects of cold-dryness on pulmonary and immunologic function of peripheral T-lymphocytes in chronic obstructive pulmonary disease （COPD） model rats, and to provide references for the prevention and treatment of cold-dryness COPD in the Xinjiang region. METHODS： The COPD model was established with an elastase drip into the trachea combined with smoking. The cold-dryness COPD model was developed by stressing with a cold-dry environment. Success of the model was determined by observation of pathologic lung sections. Rats were sacrificed by exsanguination from the femoral artery and changes of peripheral blood CD4＋, CD8＋, and CD4＋/CD8＋ were detected by flow cytometryo Data were analyzed with SAS 11.5 statistical software. RESULTS： On the ninetieth day after ending the ex- periment, Peak expiratory flow in the cold-dryness COPD group was lower than that in the COPD and normal control groups （P〈0.01）. The time of inspiration in the cold-dryness COPD group was higher than that in the COPD and normal groups （P〈0.05）. Time of expiration （Te） in the cold-dryness COPD group was higher than that in the COPD and normal groups （P〈0.01）. 50% tidal volume expiratory flow （EFS0） in the cold-dryness COPD group was lower than that in the COPD and normal groups （P〈 0.01）, and EFS0 in the COPD group was lower than that in the normal group （P〈0.05）. CD4＋ content of peripheral blood in the cold-dryness COPD group was lower than that in the COPD and the normal groups （P〈0.05）. CD8＋ content in the cold-dryness COPD and COPD groups was higher than that in the normal control group （P〈0.01）, and CD8＋ content in the cold-dryness COPD group was higher than that in the COPD group （P〈0.01）. CD4＋/CD8＋ in the cold-dryness COPD group and the COPD group was lower than that in the normal control group （P〈0.01）, and CD4＋/CD8＋ in the cold-dryness COPD group was lower than that in the COPD group （P〈0.05）. CONCLUSION： In the cold-dryness COPD model, CD8＋ increased and CD4＋/CD8＋ decreased. Moreover, cold-dryness may aggravate this state. The effects of cold-dryness on pulmonary function main- ly manifested as prolongation of Te and decrease of EF50, which could be one of causes of cold-dryness environment in the northwest of China leading to COPD with region characteristics.