Effects of ozone on transepithelial potential of mouse trachea

The effects of ozone on tracheal electrical potential were investigated in inbred strains of mice that are differentially susceptible to ozone-induced inflammation. In male mice (9-13 wk), a tracheostomy was made under pentobarbital anesthesia for spontaneous breathing and tracheal potential was measured in the cephalad portion of the bisected trachea using Hanks' salt/agar-capped KCl bridges connected to a pair of calomel half cells. The mean tracheal potentials of five different strains of mice (C3H/HeJ, DBA/2J, C57BL/6J, BALB/cJ, and 129/J) were approximately 10 mV (lumen negative) with no significant interstrain difference. Amiloride reduced mouse tracheal potentials by approximately 70% in both C3H/HeJ and C57BL/6J mice, indicating that sodium absorption is the predominant ion transport across this tissue. Relative to air-exposed controls, acute ozone exposure (2 ppm for 3 h) significantly attenuated tracheal potential of inflammation-susceptible C57BL/6J mice by approximately 50% at 6 h and 40% at 24 h postexposure but had no effect immediately after exposure. The mean tracheal potential of C3H/HeJ mice was not changed by ozone. The differential effect of acute ozone exposure on tracheal potential in C57BL/6J and C3H/HeJ mice is consistent with differential susceptibility to ozone-induced increases in epithelial permeability in these strains.