Izumi Tomiyama

Morphologic Alterations and Cytokinetic Studies of Tracheal Autograft Epithelium in Rabbits

BACKGROUND Although tracheobronchoplasty has been used widely in the field of thoracic surgery, few details of the morphologic changes in and cytokinetics of the graft epithelium have been reported. The aim of this study was to focus on these aspects in autografted rabbit tracheas. METHODS Resected cervical tracheas were anastomosed immediately after removal, retrieved on postoperative days 1 through 28, and examined morphologically. Mitotic and bromodeoxyuridine-labeling indices of the graft epithelium were analyzed. RESULTS On postoperative days 1 to 4, the graft epithelium showed focal desquamation at the anastomoses. Ciliated cells disappeared during postoperative days 4 to 7 and then increased gradually. Nonciliated cells retained a somewhat columnar shape on postoperative days 4 to 7, except at denuded foci. Thereafter, the grafts were covered completely with pseudostratified mucociliary epithelium. On postoperative day 4, both indices were maximal and appeared higher at the anastomotic than midgraft sites. CONCLUSIONS Most of the graft epithelium was preserved during acute ischemia and then started to regenerate. The increased regenerative activity near the anastomoses may be attributable to mechanical damage or different nutritional conditions.

Alkaline phosphatase reactivity in rabbit airway epithelium: a potentially useful marker for airway basal cells

The purpose of this study was to investigate alkaline phosphatase (ALPase) reactivity in rabbit airway epithelial cells. Acetone-fixed, methyl benzoate and xylene-cleared (AMeX-treated) paraffin sections of trachea, bronchus, and lung tissue were stained by an azo dye coupling method for ALPase and examined by light microscopy. Electron histochemical staining was also performed in order to study the sensitivity and specificity of reactivity in each cell type. ALPase reactivity at the light microscopic level was observed exclusively in trachco-bronchial basal cells, and not in bronchiolar basal cells. By electron microscopy, ALPase reactivity was noted in 97.9% of basal cells in the trachea, 97.0% of basal cells in the bronchus, and 94.5% of basal cells and 15.4% of Clara cells in the bronchiole. This was also true for dispersed tracheal epithelial cells. Reactivity was rarely observed in ciliated cells, non-goblet-type secretory cells, and undetermined cells. The reactivity was heatlabile, levamisole-sensitive, and of a non-specific type. These findings indicate that basal cells of rabbit trachea and bonchus have fairly high specificity for ALPase of a non-specific isozyme (92.2% and 95.6%, respectively). Therefore, ALPase is considered to be a useful marker for these cells.