The Effects of Anoxia on the Morphology and Composite Metabolism of the Intact Aortic Intima-Media Preparation

• Text
• PDF

Abstract

Paired samples of an intact rabbit aortic intima-media preparation were incubated for short periods under aerobic or anoxic conditions in Krebsbicarbonate buffer containing 6% albumin and 5 mM glucose. During aerobic incubation for as long as 1 h the preparation retained an electron microscopic (EM) appearance similar to that of tissue fixed in situ, and scanning EM confirmed the presence of an uninterrupted endothelial surface. After 2.5 min of anoxia there was widespread endothelial swelling, but the alterations in the EM appearance of these cells were not striking and did not progress during a subsequent 30 min aerobic incubation in fresh medium. After 10 min of anoxia there were marked and widespread alterations in endothelial cell structure, including loss of cell integrity, and numerous discrete interruptions in the endothelium were consistently observed on both transmission and scanning EM. After a subsequent 30 min aerobic incubation in fresh buffer, a major fraction of the luminal surface was denuded of endothelium. The aortic vascular smooth muscle cells did not exhibit evidence of irreversible anoxic injury after 2.5 or 10 min of anoxia or after subsequent aerobic incubation for 30 min. Exposure to anoxia for 10 min induced persistent alterations in the composite metabolism of the preparation during subsequent aerobic incubation in fresh medium; O2 uptake was reduced, and the fraction of the glucose uptake that was accounted for by lactate production increased approximately 100%.

Authors

Anthony D. Morrison, Lelio Orci, Leonard Berwick, Alain Perrelet, Albert I. Winegrad