An autoradiographic technique for en-face preparations of aortic endothelium

A method for the en-face preparation of aortic endothelium was developed from various different published accounts of the technique. This was adapted for autoradiography. Eighteen mice had tritiated thymidine (1 microCi/g body weight) injected and were killed 1 day later. Perfusion fixed aortae were cut into segments and placed face down on gelatin-coated slides. The arterial media and adventitia were removed and the en-face preparations coated with autoradiographic stripping film. After an exposure of 12 weeks the autoradiographs were developed and stained with Harris' haematoxylin. Labelled endothelial cells were clearly distinguishable and there was no distortion of the cells compared with other en-face and whole mount preparations. The technique described is simple, reliable and produces consistent results.