The effect of cigarette smoking on rabbit aortic elastase activity.

Twenty rabbits were divided into three groups: (1) cage controls, (2) machine controls, and (3) cigarette exposed. The cigarette-exposed group was exposed to two 2-R1 reference cigarettes a day for 6 weeks on a Walton-II (Process and Instruments Corp., Brooklyn, N.Y.) smoking machine. Rabbits in the machine control group were placed in the smoking machine for the same period of time without cigarettes. Cage control animals were not placed in the smoking machine. Aortic elastase was significantly higher in the cigarette-exposed group (21.11 +/- 6.15) compared to both the cage control group (3.11 +/- 1.11) and machine control group (14.66 +/- 4.69). Aortic elastase in the machine control group was significantly higher in smoke-exposed rabbits than in both cage control and machine control rabbits. These data indicate that cigarette smoking increases aortic elastase activity in rabbits. If these data were to be extrapolated to humans, then patients with abdominal aortic aneurysms who smoke may have an accelerated rate of aneurysm growth or earlier rupture or both.