title: Regional differences in prostaglandin E2 and nitric oxide production in the knee meniscus in response to dynamic compression.
abstract: Injury or loss of the knee meniscus is associated with altered joint stresses that lead to progressive joint degeneration. The goal of this study was to determine if dynamic mechanical compression influences the production of inflammatory mediators by meniscal cells. Dynamic compression increased prostaglandin E2 (PGE(2)) and nitric oxide (NO) production over a range of stress magnitudes (0.0125-0.5 MPa) in a manner that depended on stress magnitude and zone of tissue origin. Inner zone explants showed greater increases in PGE(2) and NO production as compared to outer zone explants. Meniscal tissue expressed NOS2 and NOS3 protein, but not NOS1. Mechanically induced NO production was blocked by NOS inhibitors, and the non-selective NOS inhibitor L-NMMA augmented PGE(2) production in the outer zone only. These findings suggest that the meniscus may serve as an intra-articular source of pro-inflammatory mediators, and that alterations in the magnitude or distribution of joint loading could significantly influence the production of these mediators in vivo.
authors.affiliation: Department of Surgery, Division of Orthopaedic Surgery, Duke University Medical Center, Box 3093, 375 Medical Sciences Research Building, Durham, NC 27710, USA.
authors.forename: Alfred
authors.initials: A
authors.lastname: Hennerbichler
authors.forename: Beverley
authors.initials: B
authors.lastname: Fermor
authors.forename: Diana
authors.initials: D
authors.lastname: Hennerbichler
authors.forename: J Brice
authors.initials: JB
authors.lastname: Weinberg
authors.forename: Farshid
authors.initials: F
authors.lastname: Guilak
mesh_terms: D000818:Animals; D019245:Compressive Strength / Q000502:physiology; D015232:Dinoprostone / Q000378:metabolism*; D005260:Female; D066298:In Vitro Techniques; D008592:Menisci, Tibial / Q000502:physiology*; D009569:Nitric Oxide / Q000378:metabolism*; D013552:Swine; D014018:Tissue Distribution; D016474:Weight-Bearing / Q000502:physiology*
chemical_list: D009569:Nitric Oxide; D015232:Dinoprostone