RESPONSES OF RAT NASAL EPITHELIUM TO SHORT-TERM AND LONG-TERM EXPOSURES OF OZONE - IMAGE-ANALYSIS OF EPITHELIAL INJURY, ADAPTATION AND REPAIR

This article reviews the use of computerized image analysis and standa rd morphologic techniques to characterize the responses of nasal epith elium in laboratory rats to single or repeated exposures to a common u rban air-pollutant, ozone. Alterations in the number and composition o f the epithelial cell populations after either short- or long-term exp osures are described. The principal nasal epithelial alteration induce d by repeated exposures to this irritating, oxidant pollutant is mucou s cell metaplasia (i.e., transformation of airway epithelium, normally devoid of mucous cells, to a secretory epithelium containing numerous mucus-secreting cells). This metaplastic change, induced by acute or chronic ozone exposures, has been morphometrically examined at various times post-exposure. In this article, we describe our current underst anding of the pathogenesis and persistence of ozone-induced mucous cel l metaplasia in nasal epithelium based on the results of these morphom etric studies. (C) 1997 Wiley-Liss, Inc.