Effects of cigarette smoke on tissue uptake and retention of iron oxide in the guinea pig.

We have previously shown that cigarette smoke increases retention and tissue penetration of asbestos, a pathogenic dust. To determine whether these same phenomena occur with an inert dust, we administered iron oxide particles to guinea pigs by intratracheal instillation. Half of the animals were exposed to cigarette smoke. Animals were killed at 1 day, 1 wk, and 1 month. Numbers of particles in airway epithelia and walls were counted in histologic sections of one lung, and the other lung was analyzed chemically for iron content. In both smoke-exposed and nonexposed groups, the chemically determined concentration of iron in the lung tissue decreased between 1 day and 1 month; however, the concentration of iron was significantly greater in the smoke-exposed group at 1 day and 1 wk. By 1 month, there was no significant difference between the 2 groups. The number of particles in the epithelia of respiratory bronchioles also decreased in both smoke-exposed and nonexposed groups between 1 day and 1 month, but the smoke-exposed group had significantly more intraepithelial particles at 1 day and 1 wk than did the nonexposed group. The number of particles in the walls of respiratory bronchioles increased between 1 day and 1 month in both smoke-exposed and nonexposed groups; the difference between these groups was significant only at 1 wk, when airway walls of the smoke-exposed animals contained more particles.(ABSTRACT TRUNCATED AT 250 WORDS)