Effects of cigarette smoke on rat thoracic aorta.

Using the fine structural macromolecular tracer horseradish peroxidase (HRP) the permeability of thoracic aorta was studied in 72 male Sprague-Dawley rats. Rats smoked for 1 day (acute effect), 14 days (subacute effect) and 15 weeks (chronic effect). Thoracic aorta sections from control rats and sham smokers were free of HRP reaction product. In smokers' thoracic aortas, permeability to peroxidase increased proportionately to the increase in length of the smoking period. Furthermore, smokers' thoracic aortas exhibited focal vacuolar dilatations (subendothelial blebs) and an increased number of subendothelial macrophages.