Journal of Applied Physiology, Vol 78, Issue 4 1330-1338, Copyright © 1995 by American Physiological Society
HOCl effects on tracheal epithelium: conductance and permeability measurements
Y. Guo, L. A. Schneider and O. D. Wangensteen
Department of Physiology, University of Minnesota, Minneapolis 55455, USA.
It is speculated that hypochlorous acid (HOCl), produced by neutrophils,
can disrupt the tracheal epithelial barrier without damage to epithelial
cells. This was investigated with solute permeability (P) and electrical
conductance (G) measurements on tracheae from 4-wk-old rabbits. A new
system for epithelial bioelectric measurements on intact tracheae was
developed and validated. Control values of G, short-circuit current, and
spontaneous potential difference were 4.9 +/- 0.5 (SE) mS/cm2, 42.6 +/- 4.7
microA/cm2, and 8.9 +/- 1.0 mV (lumen negative), respectively (n = 5).
Control P values for sucrose, inulin, and Dextran-20 were 5.14 +/- 0.48,
0.63 +/- 0.10, and 0.057 +/- 0.007 x 10(-7) cm/s, respectively (n = 6).
Tracheae treated with HOCl had no effect; 6 mM HOCl, a concentration that
could exist in infected airways, significantly increased both P and G
(about two- to fourfold) without damage to epithelial cells; and 12 and 30
mM HOCl caused more than 10-fold increases for both P and G with cell
disruption. Vitamin C blocked epithelial damage caused by 30 mM HOCl.
Tracheae from 1-wk-old rabbits were significantly more sensitive to HOCl
than those from 4-wk-old or adult rabbits. This study validated a new
bioelectric measurement system and showed that HOCl has both dose- and
age-dependent effects on the tracheal epithelium.
