[Cardiovascular effects of cigarette smoke in the rat. Aortic endothelial and myocardial capillary permeability in the rat].

The permeability of aortic endothelium and myocardial capillaries was examined in 72 Sprague-Dawley rats (approximately 350 g) using the diffusion tracer peroxidase. Animals were subjected to cigarette smoke for periods of 1 day (acute effects), 2 weeks (sub-acute effects) and 15 weeks (chronic effects) and were sacrificed 5 minutes or 8 hours after smoking. Peroxidase was not generally present at the sub-endothelial level in the aortic endothelium of control animals and sham-smokers. However, in smokers, the increase in peroxidase permeability is proportional to the smoking period. Moreover, in these smokers we observed junctional and subendothelial vacuolar dilatations which correspond to degenerative morphologic changes. Cigarette smoke has a different effect on the right ventricle. Endothelial permeability of the myocardial capillaries increases in animals subjected to cigarette smoke for 1 day and those who smoked for 2 weeks sacrificed 5 minutes after smoking. This increase in permeability is not related to the significant morphologic changes observed in the myocardium and endothelial capillaries. However, the myocardial endothelial capillaries, the sub-endothelial space and the adjacent interstitial space were generally free of peroxidase in animals subjected to cigarette smoke for 15 weeks and in those smoking for 2 weeks sacrificed 8 hours later. An adaptive phenomenon to the effects of cigarette smoke appear to exist in the myocardial endothelium capillaries contrary to that which is observed in the thoracic aorta.