Twenty vein and arterial segments from dogs were opened longitudinally, immediately pinned flat with the endothelial side up and fixed in 4% glutaraldehyde. Serial sections 20μ thick were cut. Alternate sections were stained with alcian blue and PAS. At the time of removal of the vessel from the animal, cross sections were also cut, embedded in paraffin, and stained with H&E, and elastic tissue stains. The frozen sections yielded extensive en face sheets of endothelium from the vein segments and much smaller en face areas from the arterial segments. Controls appeared normal. Veins from which the adventitia had been stripped and the vein left in situ for up to 2 yr appeared normal, with no evidence of fibrosis or other injury. Veins from which the adventitia had been stripped and the vein removed 2 hr later contained foci of extravasated erythrocytes between medial cells, foci of neutrophils within the media, a few swollen endothelial cells, and a few thrombosed vasa vasora on the adventitial surface. There was no evidence of medial necrosis or endothelial sloughing. The medial vasa vasora appeared normal and were not thrombosed. Veins which had been stripped, clamped and removed after one hr, then distended with saline, suffered injury that was minimally accentuated over that from adventitial stripping alone, but there was no evidence of irreversible injury. Medial and endothelial necrosis appeared only when the vein was made ischemic for 3 hr. Veins which had been transplanted into the arterial circulation for 2 to 3.5 yr contained multiple foci of endothelial swelling, sloughing and regeneration, with interdigitation of endothelial cells and fibroblasts, and marked fibroplasia of the media. Arterial segments which had been used as arterial grafts for 3 mth to 2.5 yr appeared normal except where they were thrombosed. At the point of attachment of the thrombus, the internal elastic membrane was completely disrupted, and the intima and media had undergone fibroplasia. There was no evidence of intimal or medial hyperplasia. This is a new technic for the examination of endothelium. The results indicate that stripping of the adventitia does not, by itself, result in any irreversible injury to vein walls or endothelium, and that arterial segments used as grafts do not necessarily undergo hyperplastic changes.
|American Journal of Pathology
|Published - Jan 1 1975
ASJC Scopus subject areas
- Pathology and Forensic Medicine