title: Effects of products from macrophages, blood mononuclear cells and or retinol on collagenase secretion and collagen synthesis in chondrocyte culture.
abstract: Collagenase secretion was studied on cultures of rabbit articular chondrocytes. Differentiation of the cells was assessed by characterizing the type of 3H-labelled collagen produced during treatment with (1) conditioned media from rabbit peritoneal macrophages and human blood mononuclear cells, and (2) with retinol, a potent cartilage resorbing agent in tissue culture. Conditioned media stimulated collagenase secretion. Total collagen synthesis was reduced due to a decrease of synthesis of alpha 1 chains; the amount of alpha 2 chains synthesized was unchanged. This is thought to be due to a reduction in type II synthesis. Retinol did not stimulate collagenase secretion. Total collagen synthesis was reduced by retinol. alpha 2 chain synthesis, however, was significantly increased, suggesting a switch of collagen synthesis in favor of type I collagen, and therefore, dedifferentiation. These results demonstrate that dedifferentiation of chondrocytes with respect to collagen synthesis is not necessarily associated with a stimulation of collagenase secretion.
mesh_terms: D000818:Animals; D002358:Cartilage, Articular / Q000187:drug effects / Q000378:metabolism*; D002478:Cells, Cultured; D003094:Collagen / Q000096:biosynthesis*; D006801:Humans; D007700:Kinetics; D008264:Macrophages / Q000502:physiology*; D003012:Microbial Collagenase / Q000378:metabolism*; D009000:Monocytes / Q000502:physiology*; D011817:Rabbits; D014801:Vitamin A / Q000494:pharmacology*
chemical_list: D014801:Vitamin A; D003094:Collagen; D003012:Microbial Collagenase