title: Antigen-induced arthritis. Studies on the inhibition of proteoglycan synthesis observed in articular cartilage during short-term joint inflammation.
abstract: During the acute phase of antigen-induced arthritis, cartilage was obtained from five different sites within the joint, and chondrocyte activity was assessed by autoradiography of sections labeled with 35S-sulfate. There was a marked inhibition of chondrocyte proteoglycan synthesis in all weight-bearing areas; in addition, the complete superficial layer of cells and many mid-zone cells in these areas were completely inactive. Electron microscopy showed that the inactive surface cells had degenerated completely, and that many mid-zone cells contained an accumulation of intracytoplasmic filaments and were depleted in biosynthetic organelles. A biochemical study of the inhibition showed that: 1) the incorporation of 35S-sulfate and 3H-acetate into glycosaminoglycans was inhibited to a similar extent; 2) the inhibition of glycosaminoglycan synthesis could not be reversed either by the addition of benzyl-beta-D-xyloside to incubations or by maintenance of the cartilage in organ culture for 6 days; 3) the inhibited chondrocytes exhibited a decreased ability to secrete proteoglycans into the extracellular fraction of the cartilage.
mesh_terms: D000818:Animals; D001168:Arthritis / Q000378:metabolism*; D001169:Arthritis, Experimental / Q000378:metabolism* / Q000473:pathology; D002358:Cartilage, Articular / Q000378:metabolism* / Q000473:pathology / Q000648:ultrastructure; D008854:Microscopy, Electron; D011509:Proteoglycans / Q000096:biosynthesis*; D011817:Rabbits; D012709:Serum Albumin / Q000008:administration & dosage / Q000494:pharmacology
chemical_list: D011509:Proteoglycans; D012709:Serum Albumin