title: Cartilage growth inhibition and necrosis in vitro caused by prostaglandin A1.
abstract: This paper details experiments using the Fell technique of organ culture of 8-day chick embryo femoral and tibial rudiments to test the effects of prostaglandin A1 (PGA1) on cartilage growth. Growth was studied during 8 days in vitro by measurement of rudiment length and wet and dry weight, and by histology. PGA1 inhibited explant growth in a dose-related manner. Linear growth was significantly decreased by 20 and 25 microgram/ml PGA1 at 2, 4, 6 and 8 days, and by 15 microgram/ml at 6 and 8 days. Linear growth was unaffected by 1 and 10 microgram/ml doses. Weight measurements were significantly reduced by 25 microgram/ml PGA1 (2, 4 and 8 days) and by 20 microgram/ml (8 days). Chondroblast degeneration was caused by doses of 15, 20 and 25 microgram/ml PGA1. Progressive degeneration was seen at the 25 microgram/ml concentration after 2 days in vitro. Cellular changes as early as 27 h in vitro were seen using electron microscopy. Tritiated thymidine autoradiography confirmed reduced chondroblast proliferation in the presence of PGA1 (25 microgram/ml). The mechanisms of prostaglandin-induced changes in embryonic cartilage remain uncertain. The possible role of intracellular cyclic nucleotides in the reaction is discussed.
mesh_terms: D000818:Animals; D001345:Autoradiography; D002356:Cartilage / Q000187:drug effects* / Q000473:pathology / Q000648:ultrastructure; D002357:Cartilage Diseases / Q000139:chemically induced; D002642:Chick Embryo; D004305:Dose-Response Relationship, Drug; D008854:Microscopy, Electron; D009336:Necrosis; D011454:Prostaglandins A / Q000494:pharmacology*
chemical_list: D011454:Prostaglandins A