BACKGROUNDRe-epithelialization has remained a major obstacle in both tracheal and lung transplantations. This study examines the realization of re-epithelialization by epithelial inoculation in a rat heterotopic tracheal transplantation model.

METHODSThe original epithelia of tracheas from donor Wistar rats were removed and the tracheas were then inoculated with 10(6)/ml in vitro cultured epithelial cells of the Spraque-Dawley (SD) rat phenotype. These allo-tracheas were then heterotopically transplanted into SD rats. After 28 days, the allo-trachea tissues were recovered and assessed for epithelial morphology and cellular differentiation using immunohistochemical analysis. An additional experimental group was used to compare the outcomes of re-epithelialization in immunosuppressed animals.

RESULTSHistological examination showed that allografts with epithelial inoculation maintained patent tracheal lumens, which were obliterated in controls. Recipient immunosuppression facilitated the formation of an integrated ciliated epithelial layer, further demonstrated by the presence of a dense cilia population, a well-developed plasma membrane, and readily recognizable intercellular junctions. Epithelial cellular differentiation markers such as cytokeratin 14 and 18, and cystic fibrosis transmembrane conductance regulator (CFTR) were all positive in allografts under immunosuppression.

CONCLUSIONConcurrent recipient-derived epithelial inoculation with immunosuppression can result in complete re-epithelialization with the recipient phenotype and suppress the luminal obliteration process in heterotopic transplantations.