Formation of an atypical collagen and cartilage pattern in limb bud cultures by highly sulfated GAG.

Addition of 1 mg/ml or higher doses of the highly sulfated pentosanpolysulfoester SP54 or the mucopolysaccharidepolysulfoester Arteparon to limb bud cultures from 11-day-old mouse embryos caused a marked reduction in the growth of the distal parts of the cartilage anlagen. The most striking effect, however, was the change in the collagen structure of the cartilaginous intercellular substance. After more than 0.05 mg/ml SP54 or Arteparon no collagen filaments were seen but collagen aggregates with an altered cross-striation occurred. They were produced by an antiparallel arrangement of collagen molecules caused by the highly sulfated substances. By immunofluorescence microscopy it was shown that SP54 and Arteparon did not influence the distribution of the collagen types but only affected the aggregation of collagen type II. From the morphological point of view the production of endogenous PG seemed to be uneffected by SP54 and Arteparon. The effect of SP54 and Arteparon was reversible. After removal of these substances characteristic collagen filaments re-formed. The collagen aggregates were decomposed extracellularly or phagocytosed by chondroblasts and decomposed intracellularly.