Study of prevention effect of erythromycin on tracheal stenosis in tracheal injury rabbit models

Objective To explore the mechanism of prevention effect of erythromycin on tracheal stenosis in tracheal injury rabbit models. Methods Eighteen rabbits were randomly divided into three groups.The trachea were directly closed after tracheotomy in negative control group, the tracheal mucosa was scraped by a nylon brush after tracheotomy in model control group and erythromycin treated group.On the seventh day before operation, the rabbits in erythromycin treated group received intragastric administration of 13.6 mg/kg erythromycin daily until the tenth day after operation, the rabbits in negative control group and model control group received equivalent saline daily.Pathological changes and the degree of stenosis were assessed by hematoxylin and eosin staining, transforming growth factor-β1 (TGF-β1) mRNA expression was determined by real-time polymerase chain reaction, and the expressions of type Ⅰcollagen and type Ⅲ collagen were detected by immunohistochemistry. Results The tracheal stenosis rate was respectively (35.11±4.50)%, (11.96±3.26)%, and (53.95±7.09)% in erythromycin treated group, negative control group, and model control group. The tracheal stenosis rate in erythromycin treated group was lower than that in model control group (t=13.98, P<0.05). Pathology result showed more inflammatory cell infiltration, fibroblast proliferation, and a large number of small angiogenesis in model control group, but these features were reduced in erythromycin treated group.The expression of TGF-β1 mRNA in erythromycin treated group was lower than that in model control group (t=4.55, P<0.05). Immunohistochemistry result showed that the expressions of typeⅠcollagen and type Ⅲ collagen in tracheal stenosis tissue of erythromycin treated group were down-regulated compared with model control group (all P<0.05). Conclusions Erythromycin has a preventive effect on tracheal stenosis through the down-regulation of expressions of TGF-β1, typeⅠcollagen and type Ⅲ collagen in tracheal injury rabbits. Key words: Erythromycin; Tracheal injury; Tracheal stenosis; Transforming growth factor-β1; TypeⅠcollagen; Type Ⅲ collagen