Effects of vitamin A-deprivation on hamster tracheal epithelium

Abstract

The effects of vitamin A-deprivation on the tracheal epithelium were studied in 35-day old hamsters that had been raised since birth on a vitamin A-deficient diet. Colchicine and³HTdR were given 6 hours before death and the proliferative activities of basal cells and mucous cells were quantified separately by³HTdR labeling indices and mitotic rates. Vitamin A-deprivation decreased replication of basal cells and mucous cells in tracheal epithelium which showed minimal morphologic change. The mitotic rates and labeling indices were reduced 3 to 4-fold in basal cells and 14-fold in mucous cells (analyzed as percent of total number of each cell type) compared with controls. Thus, replication of mucous cells was more inhibited by lack of vitamin A, than replication of basal cells. The disparatehypoplasia of basal cells and mucous cells in epithelium showing minimal change, resulted in a relative increase in the proportion of basal cells and a relative decrease in the proportion of mucous cells, which could be erroneously interpreted as “basal cell hyperplasia”. Proportions of preciliated and ciliated cells were also decreased compared to controls. At foci of stratification and epidermoid metaplasia, cell replication rates were increased over controls and more than 70% of all mitotic activity was associated with “non-basal” cells. Genesis of these lesions The opinions and assertions contained herein are the private views of the authors and are not to be construed official or as reflecting the views of the Department of Defense The experiments reported herein were conducted according to the principles set forth in the “Guide for the Care and Use of Laboratory Animals” Institute of Laboratory Animal Resources, National Research Council, DHSW Publ. No. 78-23 This is contribution No. 1554 from the Cellular Pathobiology Laboratory of the Department of Pathology, University of Maryland School of Medicine was coincident with cell death and cell loss. The histogenesis of stratification and epidermoid metaplasia was characterized. Morphological evidence indicated that these lesions were closely related histogenetically and were composed, for the most part, of altered mucous cells which expressed dual phenotypes i.e. keratinization and mucus synthesis.