Journal of Applied Physiology, Vol 60, Issue 2 416-426, Copyright © 1986 by American Physiological Society
Effects of sulfur dioxide on pore populations of canine tracheal epithelium
S. F. Man, W. C. Hulbert, K. Mok, T. Ryan and A. B. Thomson
The bioelectric and barrier properties of the tracheal epithelium in
nose-breathing dogs and in dogs that had been exposed for 75 min to
compressed air or to two high concentrations of SO2 were measured and
compared. We also studied tissues that had been treated with chloroform.
Based on a model of restrictive diffusion we demonstrated heteropores (6
and 250 A) in the control tissues. Bioelectric changes due to 100-ppm SO2
were minimal. After exposure to 500 ppm SO2, adverse changes in the
bioelectric properties were focal; they were marked in 8 out of 12 animals
but were less striking in the other 4. Nonelectrolyte permeability
increased with an increase in SO2 concentrations. Small pores were still
present in the tissues severely affected by SO2 but they were absent in
chloroform-treated tissues. Scanning electron microscopy of tissues from
animals exposed to 500 ppm SO2 showed that in the same dog tissue
appearance varied from normal to one of repair (normal bioelectric
properties) or one of marked exfoliation of ciliated cells (abnormal
bioelectric measurements).
