A role for the interleukin-1 receptor in the pathway linking static mechanical compression to decreased proteoglycan synthesis in surface articular cartilage.
Loading of articular cartilage during weight bearing is essential for the maintenance of cartilage function. Although certain cyclic loading protocols stimulate extracellular matrix synthesis, constant or static compression decreases proteoglycan and collagen synthesis in cartilage explants. The goal of this study was to determine whether the compression-induced decrease in proteoglycan synthesis involves an interleukin-1 (IL-1) signaling pathway. Cartilage explants were compressed 50% in the presence of IL-1 receptor antagonist (IL-1ra), and the incorporation of [35S]sulfate into macromolecules was measured. IL-1ra increased sulfate incorporation in compressed cartilage but not in cartilage maintained at the in situ thickness (0% compression). IL-1alpha and IL-1beta mRNAs were detected in cartilage compressed 50% for at least 3h, while nitric oxide synthase II mRNA was only detected in cartilage compressed 50% for 6h. The data support a role for the IL-1 receptor in the pathway linking static compression to reduced proteoglycan synthesis.
Orthopaedic Research Laboratories, Department of Orthopaedic Surgery, Massachusetts General Hospital and Harvard Medical School, 55 Fruit Street, Boston, MA 02114, USA.
Minako
M
Murata
Lawrence J
LJ
Bonassar
Marianne
M
Wright
Henry J
HJ
Mankin
Christine A
CA
Towle
D000818:Animals; D002356:Cartilage / Q000378:metabolism* / Q000502:physiology; D002358:Cartilage, Articular / Q000378:metabolism*; D002417:Cattle; D004305:Dose-Response Relationship, Drug; D006025:Glycosaminoglycans / Q000378:metabolism; D006801:Humans; D007375:Interleukin-1 / Q000378:metabolism; D007700:Kinetics; D019001:Nitric Oxide Synthase / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II; D011509:Proteoglycans / Q000378:metabolism*; D012313:RNA / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D017472:Receptors, Interleukin-1 / Q000378:metabolism / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013314:Stress, Mechanical; D013997:Time Factors
D006025:Glycosaminoglycans; D007375:Interleukin-1; D011509:Proteoglycans; D012333:RNA, Messenger; D017472:Receptors, Interleukin-1; D012313:RNA; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II