A histological and histochemical study on glycosaminoglycans in epiphysial cartilage of osteochondrodysplasia rat (OCD/OCD).

The osteochondrodysplasia rat, inherited by a single autosomal recessive lethal gene ocd, shows a typical dwarfing syndrome with systemic subcutaneous edema. The skeletal system is most severely affected. The affected neonates are associated with cleft palate, abnormal kidney position and central nerve system malfunction. The present study describes histological and histochemical appearances of the affected epiphysial cartilage. Irregular columnization, thinner hypertrophic zone, swelled chondrocytes, tightly packed chondrocytes with a poor amount of cartilage matrix was found in the affected. The defining characteristic was a wide-spread degenerating area from the resting to hypertrophic zone. The extracellular matrix (ECM) reacted weakly for the glycosaminoglycans (GAGs). A reduced content of sialic acid in the ECM was suggested. It is concluded that the cartilage abnormalities in the ocd/ocd is a new type disease of osteochondrodysplasia possibly due to some defects in GAGs and/or sialic acid metabolism.