Heterogeneity of the composition and thickness of tracheal mucus in rats.
Inability to preserve airway mucus in situ has limited our understanding of its structure and function. This light- and transmission electron-microscopic study of rat tracheal mucus used a nonaqueous fixative that retains mucus (epiphase) over a lucent layer (hypophase). The fixative is a 1% solution of osmium tetroxide dissolved in a perfluorocarbon. The mean thickness of rat tracheal epiphase was 5 microns, with significant variation (0.1-50 microns) around the tracheal circumference. Tracheal mucus was thickest at the trachealis muscle region and contained cells, cellular debris, and a variable amount of surfactant and lipid, estimated at 4-16% of the total epiphase in five rats, with a mean composition of 9%. Lipid was observed on the surface of the epiphase, embedded within mucus, and at the epiphase-hypophase interface. Refined study of developmental, physiological, and pathological alterations to the airway coat may benefit from this approach.
Sims
D E
DE
Department of Anatomy and Physiology, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Canada. sims@upei.ca
Horne
M M
MM
D000818:Animals; D004396:Coloring Agents; D008854:Microscopy, Electron; D009092:Mucous Membrane / Q000033:anatomy & histology / Q000166:cytology / Q000648:ultrastructure; D009130:Muscle, Smooth / Q000033:anatomy & histology; D051381:Rats / Q000033:anatomy & histology*; D017207:Rats, Sprague-Dawley / Q000033:anatomy & histology*; D014132:Trachea / Q000033:anatomy & histology* / Q000166:cytology
D004396:Coloring Agents