Elastin-proteoglycans association revealed by cytochemical methods.

By using various cytochemical stains, proteoglycans are shown to be present inside elastic fibers in aortas of beta-aminopropionitrile-induced lathyritic chicks. Depending on the characteristics of the dyes, the shape, size and distribution of the proteoglycan-revealing precipitates are described. The monocationic dye toluidine blue O and the tetracationic dye Alcian blue in the presence of 0.3 M MgCl2 give the most detailed results. With these stains the proteoglycans inside lathyritic elastin appear to be lateral branches of matrix proteoglycans, lying on the external surface of the elastic fibers. A possible general biological significance of elastin-proteoglycan association is briefly discussed.