Eur J Anat, 4 (2): 69-81 (2000)

Experimental autotransplantation of the trachea: Structural changes studied in the rabbit with a reference to human tracheal stenosis

Zagalo C., Grande N.R., Martins dos Santos J., Monteiro E., Aguas A.P.

Department of Anatomy, Institute for Biomedical Sciences, Porto University, L. Abel Salazar 2, 4099-033 Porto, Portugal

ABSTRACT Transplantation of the trachea is envisaged as the treatment of the future for severe cases of tracheal stenosis. In order to investigate the structural consequences of tracheal transplantation, we studied the adaptive changes of tracheal autografting in the rabbit. We found that auto-transplantation of long portions of the trachea (involving 10 cartilage rings) was not viable in the rabbit, in contrast with the complete success observed after grafting of 4-ring segments of trachea. We report here on the morphological modifications of the trachea in these successful 4-ring autograftings of the organ. Marked epithelial alterations were seen in the early stage (one week) of the tracheal autografting, consisting of the loss of cilia and increase in the number of mucous cells. Two weeks after surgery, there was evidence of partial recovery by the epithelium. At three months after autografting, the epithelium was almost completely covered with cilia, the submucosa was poor in elastic fibers and cartilage foci were found outside the rings. Six months after surgery, the entire luminal surface of the rabbit trachea was covered with cilia; these samples showed discontinuities in the basement membrane and a paucity in elastic fibers. Major alterations were detected in the cartilage components of the autografted trachea, consisting in the fusion of adjacent rings and, at the suture lines, partial superimposition of rings. We conclude that the epithelium and the cartilage components of the trachea show distinct responses to autografting: changes in the epithelium are severe in the acute phase but are transitory and disappear in the long run, whereas alterations of the cartilage are initially less conspicuous but slowly develop into the neoformation of cartilage tissue with fusion and superimposition of some tracheal rings, causing moderate tracheal stenosis.

Keywords: adult, animal cell, animal experiment, animal model, animal tissue, article, autograft, autotransplantation, cartilage, case report, ciliated epithelium, controlled study, female, human, male, nonhuman, rabbit, trachea stenosis, treatment outcome