An evaluation by sequential extraction of the proportions of collagen types from medium sized arteries.

Samples of human Common Iliac Arteries, obtained post-mortem from patients without evidence of atherosclerosis, were analyzed for their content in the various types of collagens using alternatively sonication, pepsin digestion and dithiothreitol reduction followed by sodium dodecyl sulfate polyacrylamide gel electrophoresis of the extracts. A final average proportion of 66% of the total collagen was solubilized. The statistical calculation of the proportions of the different collagens, deduced from the densitometric scannings of the electrophoretic runs, showed that a larger amount of type I was extracted when the extraction was more complete. Type I collagen appeared as the most insoluble collagen in these arteries and its final proportion was probably higher than 60% of the total collagen.