Elastin fiber-associated glycosaminoglycans in beta-aminopropionitrile-induced lathyrism

Ruthenium red and toluidine blue O precipitates were described associated with lathyritic elastic fibers in aortas of chickens treated with beta-aminopropionitrile fumarate (I. Pasquali-Ronchetti, C. Fornieri, I. Castellani, G. M. Bressan, and D. Volpin (1981). Alterations of the connective tissue components induced by beta-aminopropionitrile. Exp. Mol. Pathol. 35, 42-56). In this report evidence is given that these precipitates reveal the presence of proteoglycans, as they are completely removed by 5 M guanidine-HCl incubation and by specific enzymatic digestions. In particular, proteoglycans associated with the poorly cross-linked lathyritic elastin can be removed by testicular hyaluronidase, chondroitinase ABC, heparitinase, and nitrous acid treatments, whereas they are rather resistant to streptococcal hyaluronidase and chondroitinase AC. On the contrary, proteoglycans of the matrix or associated with collagen fibers are particularly sensitive to these latter enzymatic treatments. The conclusion is reached that glycosaminoglycans associated with beta-aminopropionitrile-induced lathyritic elastin (i) are different from those of the matrix or associated with collagen, and (ii) include mainly dermatan and heparan sulfates.