Smokeless tobacco-induced lamellar body abnormalities.

Objectives: To compare the morphological changes and quantitative distribution of lamellar bodies (Lb) (membrane coating granules) in the hamster cheek pouch epithelium with smokeless tobacco (ST). Materials and methods: Archives of experimental material from previously published studies [S. Ashrafi, A. Das, R. Worawongvasu, B. Mehdinejad and J. Waterhouse (1992) Scanning Microscopy 6: 183] were utilized. Animals in experimental group received most ST (snuff) in their right pouch, 5 days weekly, for 24 months, while no snuff was given to control group. After 24 months, the epithelial tissues were processed for electron microscopic study. Volume densities of Lb were assessed by morphometry. Main outcome measures: Densities of Lb in the two groups, experimental vs control. Results: In the control, Lb extruded their contents into the intercellular spaces of upper granular layers and in between the last granular cell layers and keratin layers to form a permeability barrier. Conversely, in the smokeless tobacco-treated epithelium, the majority of the Lb that were formed remained inside and accumulated within the granular cells, without extruding their contents into the intercellular spaces to form a lipid compound permeability barrier. Conclusions: Commercial alkaline ST may have contributed to the abnormal accumulation of Lb in the granular cell layer and affected the extrusion process of Lb to form an incomplete permeability barrier in the oral epithelium. [ABSTRACT FROM AUTHOR]