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Protective effects of intermittent hydrostatic pressure on osteoarthritic chondrocytes activated by bacterial endotoxin in vitro
Author(s) -
Lee Mel S.,
Ikenoue Takashi,
Trindade Michael C. D.,
Wong Neal,
Goodman Stuart B.,
Schurman David J.,
Smith R. Lane
Publication year - 2003
Publication title -
journal of orthopaedic research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.041
H-Index - 155
eISSN - 1554-527X
pISSN - 0736-0266
DOI - 10.1016/s0736-0266(02)00085-2
Subject(s) - chondrocyte , lipopolysaccharide , aggrecan , nitric oxide , monocyte , chemistry , hydrostatic pressure , chemotaxis , downregulation and upregulation , synovial fluid , inflammation , nitric oxide synthase , microbiology and biotechnology , endocrinology , medicine , osteoarthritis , in vitro , biochemistry , biology , receptor , pathology , articular cartilage , physics , alternative medicine , organic chemistry , gene , thermodynamics
The role of continuous passive motion (CPM) in the management of septic arthritis and inflammatory arthritis remains of interest. CPM produces cyclic variations in intraarticular pressure that facilitates transport of fluid, nutrients, and solutes within and/or across the joint and stimulates chondrocyte metabolism. However, the precise mechanisms mediating the responses of chondrocytes to joint motion remain unclear. This study tested the hypothesis that dynamic mechanical loading counteracts effects of bacterial lipopolysaccharide (LPS), an inflammatory mediator, on chondrocyte metabolism. Intermittent hydrostatic pressure (IHP) (10 MPa for 4 h) was applied to human chondrocytes pretreated with LPS (1 μg/ml for 18 h). LPS activation of chondrocytes decreased mRNA signal levels of type II collagen by 67% and aggrecan by 56% and increased nitric oxide by 3.1‐fold, monocyte chemotactic protein‐1 mRNA signal levels by 6.5‐fold, and matrix metalloproteinase‐2 mRNA signal levels by 1.3‐fold. Application of IHP to LPS‐activated chondrocytes decreased nitric oxide synthase mRNA signal levels and nitric oxide levels in the culture medium. Exposure of LPS‐activated chondrocytes to IHP upregulated type II collagen and aggrecan mRNA signal levels by 1.7‐fold, relative to chondrocytes activated by LPS and maintained without loading. In addition, application of IHP decreased the upregulation in signal levels of monocyte chemotactic factor‐1 and matrix metalloproteinase‐2 following LPS activation by 45% and 15%, respectively. These data show that mechanical loading counteract effects of inflammatory agents, such as bacterial LPS, and suggest that postinfection sequelae are influenced by the presence or absence of joint loading. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.