[Collagen proteins of human hyaline cartilage in normal states and in various bone dysplasias].

Using SDS electrophoresis and subsequent densitometry, isolated collagen proteins of infantile rib and knee joint hyaline cartilage were characterized. Both the normal samples and hyaline cartilages of children with osteochondrodysplasias were shown to contain collagens type I and II as well as collagen proteins with Mr 160 (A), 150 (B), 140 (C), 120 (D), 110 (E) and 39 kD (F), whose content in normal samples varied, depending on the donor age. An analysis of normal and pathological samples revealed the following biochemical markers of intensive chondrocyte proliferation: an increased content of collagen proteins A--F and a decreased number of intramolecular cross-links of collagen type II. Conversely, the increased number of intramolecular cross-links in collagen type II and the elevation of the relative content of collagen type I in lethal forms of osteochondrodysplasias and funnel chest may testify to chondrocyte dedifferentiation. It was assumed that collagen proteins D and E correspond to proteins 1 alpha and 2 alpha, whereas proteins A, B, C and F are the products of hydrolysis by pepsin type M of collagen detected previously only in animal cartilages. Mapping of collagen type II CNBr-peptides and electron microscopic analysis of its SLS-form were carried out. The experimental results are suggestive of the involvement of collagen proteins in the pathogenesis of human osteochondridysplasias as well as of the pronounced biochemical heterogeneity of the disease.