Abstract: AIM: To observe the effect of tranilast on experimental COPD rats in terms of airway remodeling.METHODS: Forty eight SD rats were divided into two groups in random:untreated model group, tranilast-treated grouP.Another eight rats were selected as control grouP.The COPD rat model was established by passive smoking and intratracheal instillation of lipopolysaccharide( LPS) and then treated with sterile saline or tranilast( 400 mg·kg^-1·d^-1 ) respectively.Eight rats in each grouPwere killed in 7th, 14th, 28th day after the beginning of proceeding.Bronchoalveolar lavage fluid ( BALF) was collected, and the total and differential cells were counted.The distribution and the ratio of type I to type III collagen in the lung tissue were determined using a sirius red polarizing microscopy morphometry method.Lung tissues were observed by hemotoxylin and eosin stain, then the image analysis were made.RESULTS: The total cells and the AM ratio in BALF of tranilasttreated grouPsignificantly decreased in comparison with those in model grouP( P<0.05) ;compared with control group, model grouPcollagen deposition increased and predominant type Ⅰ collagen presented in 28th day.Type Ⅰ collagen deposition in treated grouPwas lower than that in model grouPbut still higher than that in control grouP.Image analysis suggested that the airway wall thickness,the vessel thickness and the ratio of gland thickness airway wall thickness were significantly smaller than that in model grouP( P<0.05).CONCLUSION: Tranilast can lessen airway remodeling of COPD rat models through decreased the AM and type Ⅰ collagen deposition in the airway.

Key words: tranilast, chronic obstructive pulmonary disease, bronchoalveolar lavage fluid, collagen, airway remodeling