title: Single impact trauma in human early-stage osteoarthritic cartilage: implication of prostaglandin D2 but no additive effect of IL-1β on cell survival.
abstract: Injury to articular cartilage is often associated with an inflammatory reaction and frequently results in the development of post-traumatic osteoarthritis (post-traumatic OA). Cell death, inflammation and loss of proteoglycans participate in these mechanisms with p38MAPK being one of the pivotal signaling kinases. Therefore, the interaction of trauma and of the pro-inflammatory cytokine IL-1β was investigated in an in vitro tissue model of human osteoarthritic cartilage. Trauma was induced by impacting cartilage explants with a drop-tower system and its effect was measured in terms of cell survival, gene expression and the release of mediators. In addition, the effect of concomitant IL‑1β stimulation and p38MAPK inhibition by SB203580 was investigated. We found a significant decrease in chondrocyte viability after trauma, but no additional effect of IL-1β stimulation. SB203580 had a tendency to improve cell survival suggesting a role for p38 signaling in cell viability after impact in an inflammatory environment. We showed that various mediators are released in response to trauma with or without IL-1β stimulation, differing in composition and time response. Trauma resulted in an increased release of IL-6, whereas TNF-α and IL-1β release was unaffected. Prostaglandin (PG) and NO synthesis pathways were both affected by trauma and/or IL-1β. We demonstrate for the first time an elevated release of prostaglandin D2 (PGD2) by human articular cartilage in response to a single mechanical impact. The up-regulation of mediators was time-dependent, with a more early increase of PGD2 compared to prostaglandin E2 (PGE2) and a late induction of NO by co-stimulation with IL-1β between 6 and 24 h.
authors.affiliation: Division for Biochemistry of Joint and Connective Tissue Diseases, Department of Orthopedics, University of Ulm, Ulm, Germany.
authors.forename: Helga
authors.initials: H
authors.lastname: Joos
authors.forename: Cathrin
authors.initials: C
authors.lastname: Hogrefe
authors.forename: Lucia
authors.initials: L
authors.lastname: Rieger
authors.forename: Lutz
authors.initials: L
authors.lastname: Dürselen
authors.forename: Anita
authors.initials: A
authors.lastname: Ignatius
authors.forename: Rolf E
authors.initials: RE
authors.lastname: Brenner
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002358:Cartilage, Articular / Q000187:drug effects / Q000293:injuries*; D002470:Cell Survival / Q000187:drug effects; D019902:Chondrocytes / Q000187:drug effects / Q000378:metabolism; D016207:Cytokines / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005786:Gene Expression Regulation; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D018836:Inflammation Mediators / Q000494:pharmacology*; D053583:Interleukin-1beta / Q000494:pharmacology*; D008875:Middle Aged; D052247:Nitric Oxide Synthase Type II / Q000235:genetics / Q000378:metabolism; D010003:Osteoarthritis / Q000235:genetics / Q000378:metabolism*; D015230:Prostaglandin D2 / Q000378:metabolism*; D011725:Pyridines / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects; D015854:Up-Regulation; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors
chemical_list: D016207:Cytokines; D004791:Enzyme Inhibitors; D007093:Imidazoles; D018836:Inflammation Mediators; D053583:Interleukin-1beta; D011725:Pyridines; C496319:NOS2 protein, human; D052247:Nitric Oxide Synthase Type II; D048051:p38 Mitogen-Activated Protein Kinases; C093642:SB 203580; D015230:Prostaglandin D2