Role Of Reepithelization In Preventing Posttransplanted Obliterative Airway Disease

Objective To investigate the role of reepithelization of tracheal and bronchial allografts with recipient-drived musoca in prevention of obliterative airway disease after airway transplantation.Method Obtaining BALB/c mouse's tracheal and bronchiol allografts as donor, tracheal allografts were orthotopically transplanted into major histocompatability mismatched C57BL/6 mouse (recipient).In the treated group, bronchiol allografts were ligated adjacent to the recipient's trachus while in the untreated group , bronchial allografts were not ligated which gave ricipient's musoca opportunity to immigrate into the bronchial allografts. Allografts were removed on 28 day after transplantation for histology, computerized morphometry and immunohistochemical detection of the phenotype of epithelium.Results Tacheal allografts and unligated bronchiol allografts exhibited luminal patency while ligated bronchiol allografts were obliterated with fibrous tissue and abundant fibroblasts described as OAD. Airway edema and cellular infiltration of the lamina propria were found in allografts. In ligated bronchiol allografts the fibrous tissue and fibroblasts of the lamina propria was much more than that of the unligated bronchiol allografts (p=0.041). Partially ciliated cuboidal or attenuated epithelium completely covered the lumen. The cilliary coverage of normal trachea,tracheal allografts in unligated groups,tracheal allografts allografts in ligated groups and unligated bronchio allogrofts was ,on average, 91.0%,39.8%,49.2%,19.3%, respectively. The cilliary coverage of unligated bronchio allogrofts was much lower than that of tracheal allografts in ligated groups and unligated groups(p=0.000,0.007). Immunohistochemical analysis demonstrated that orthotopic tracheal allografts and unligated bronchiol allografts epithelium expressed recipient phenotype while ligated bronchiol allografts which had OAD did not express recipient phenotype.Conclusion Orthotopic tracheal allografts and unligaget bronchiol allografts undergo reepithelization with recipient-drived mucosa and this process prevent the development of OAD through regulating the fibroblasts of the lamina propria.