EFFECT OF EXPOSURE OF GUINEA-PIGS TO CIGARETTE-SMOKE ON ELASTOLYTIC ACTIVITY OF PULMONARY MACROPHAGES

Study objective: To determine the effect of exposure to cigarette smok e on the elastolytic activity of guinea pig's alveolar macrophages (AM s), and to compare elastolytic activity of AMs obtained by BAL with th at of lung macrophages (LMs) obtained from minced lung tissue. Methods : AMs were obtained by BAL from seven adult guinea pigs exposed to cig arette smoke for 5 d/wk during 6 weeks, as well as from age-matched co ntrol guinea pigs. From each animal, one lung was used to obtain LMs b y mincing and teasing the lung, followed by enzymatic digestion and is olation of mononuclear cells by Hypaque-Ficoll separation. The other l ung was inflated and fixed to quantitate emphysema by the destructive index (DI). Elastolytic activity (microgram of elastin degraded by 10( 6) macrophages) was determined at 24, 48, and 72 h, by culturing AMs a nd LMs (1x10(6) cells in 1 mL of medium) in H-3-elastin-coated wells. Results: In animals exposed to cigarette smoke, the total number of BA L cells (8.6+/-2.1x10(6)) and DI (21.8+/-8.1) were significantly highe r than in nonexposed animals (6.4+/-1.8x10(6), P<0.05 for cells, and 1 2.1+/-4.1, p<0.01 for DI). Elastolytic activity of AMs from smoke-expo sed guinea pigs was significantly higher at 24, 48, 72 h than elastoly tic activity of AMs from control animals (19.0+/-9.4 vs 10.0+/-5.3, p< 0.05 at 72 h). Likewise, elastolytic activity of LMs was significantly higher in exposed than nonexposed guinea pigs (11.8+/-7.7 vs 7.4+/-5. 0 at 72 h, p<0.05). Elastolytic activity of LMs was not significantly different from elastolytic activity of AMs, both in exposed guinea pig s (11.8+/-7.7 vs 19.0+/-9.4 at 72 h) and nonexposed animals (7.4+/-5.0 vs 10.0+/-5.3 at 72 h). Conclusions: The results indicate that elasto lytic activity of both AMs and LMs of guinea pigs increases significan tly after exposure to cigarette smoke and that AMs and LMs have simila r elastolytic activities.