Methodological approaches for the study of the aortic endothelium of the rat.

This report describes a new method for obtaining whole mount preparations of rat thoracic aorta which allows the study en face of the complete surface of the endothelium. A comparative study of the different techniques utilized for silver staining of endothelium has been performed. Included is the description of an apparatus for perfusion fixation of rat aorta which allows sequential perfusion of several fluids at a constant pressure. Conditions for perfusion fixation at physiological pressure and flow and for optimal nuclear staining and silver staining of the interendothelial junctions have been studied. The method is rapid and easy to perform and, in the same preparation, allows by optical microscopy the study of the most commonly described parameters for the characterization of normal and injured endothelium. Qualitative aspects of the endothelial lesions found in rats with antibodies to Mycoplasma pulmonis are presented.