Scanning electron microscopic observations of common carotid artery endothelium in the rat. I. Crater artifacts.

Changes in the endothelial surface of the common carotid artery of the Sprague-Dawley rat were observed by scanning electron microscopy after vessels were removed prior to sacrifice or after gluteraldehyde cardiac perfusion. Rates were classified according to whether the vessels was 1) untouched prior to removal, 2) dissected and observed for a period of time, and 3) clamped and observed. Changes consisted of small 1-6 micron craters as well as smooth or cross-striated endothelial ridges or folds. Clamped arteries appeared to exhibit more frequent craters. In contrast, vessels removed prior to death and briefly washed with saline exhibited craters different morphologically from those vessels perfused with gluteraldehyde. Background endothelial folds also differed from the gluteraldehyde-perfused group, exhibiting a cobblestoned or breaded appearance with distorted endothelial bridges. This supports the suggestion of Nelson that premortem perfusion of heart and ascending aorta with gluteraldehyde is necessary to reduce artifact in arterial endothelial structures.